1p36 deletion syndrome facts Introduction to the 1p36 deletion syndrome – how individuals get chromosomes with missing DNA 1p36 deletion syndrome stands for the following: 1 is the chromosome number that has deleted ...

Seborrheic Keratosis is a skin disorder usually characterized by discolored lesions that appear to be "stuck on" the skin surface. Warts may appear and skin is often oily or greasy. These skin lesions are sometimes mistaken for cancerous growths a...

Cayler syndrome, also known as "asymmetric crying facies with cardiac defects," is an extremely rare disorder characterized by congenital heart defects and the underdevelopment or absence of one of the muscles that control the movements of the low...

Cayler syndrome, also known as "asymmetric crying facies with cardiac defects," is an extremely rare disorder characterized by congenital heart defects and the underdevelopment or absence of one of the muscles that control the movements of the low...

Achard-Thiers syndrome is a rare disorder that occurs primarily in postmenopausal women and is characterized by type 2 (insulin-resistant) diabetes mellitus and signs of androgen excess. The exact cause of this syndrome is unknown....

Hereditary spherocytic hemolytic anemia is a rare blood disorder characterized by defects within red blood cells (intracorpuscular) that result in a shortened survival time for these cells. Red blood cells (erythrocytes) normally circulate for a f...

A rare genetic condition where the body can't process proteins adequately. More specifically, there are insufficient levels of the enzyme needed to break down an amino acid called leucine. This results in a build up of isovaleric acid which can harm ...

Acne is a skin condition that occurs when your hair follicles become plugged with oil and dead skin cells. It often causes whiteheads, blackheads or pimples, and usually appears on the face, forehead, chest, upper back and shoulders. Acne is most ...

Acne (acne vulgaris, common acne) is a disease of the hair follicles of the face, chest, and back that affects almost all teenagers during puberty -- the only exception being members of a few primitive Neolithic tribes living in isolatio...

Understanding the key reason of adult-onset asthma and identifying unique phenotypes may hel...

Acquired agranulocytosis is a rare, drug-induced blood disorder that is characterized by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood. The name granulocyte refers to grain-like bodies within the cel...

A blood disorder characterized by low levels of white blood cells (granular leukocytes) in the circulating blood. The condition is usually caused by certain drugs especially chemotherapy drugs....

Classical lissencephaly, also known as lissencephaly type I, is a brain malformation that may occur as an isolated abnormality (isolated lissencephaly sequence [ILS]) or in association with certain underlying syndromes (e.g., Miller-Dieker syndrom...

Osteopetrosis may be inherited as either a dominant or recessive trait and is marked by increased bone density, brittle bones, and, in some cases, skeletal abnormalities. Although symptoms may not initially be apparent in people with mild forms of...

The term albinism typically refers to oculocutaneous (ok-u-low-ku-TAY-nee-us) albinism (OCA) — a group of inherited disorders where there is little or no production of the pigment melanin. The type and amount of melanin your body produces de...

Primary aldosteronism (al-DOS-tuh-ro-niz-um) is a type of hormonal disorder that leads to high blood pressure. Your adrenal glands produce a number of essential hormones. One of these is aldosterone, which balances sodium and potassium in your blo...

Alzheimer's disease is a progressive neurologic disorder that causes the brain to shrink (atrophy) and brain cells to die. Alzheimer's disease is the most common cause of dementia — a continuous decline in thinking, behavioral and social ski...

Alzheimer's disease is a progressive neurologic disorder that causes the brain to shrink (atrophy) and brain cells to die. Alzheimer's disease is the most common cause of dementia — a continuous decline in thinking, behavioral and social ski...

Amyotrophic lateral sclerosis facts Amyotrophic lateral sclerosis is a rapidly progressive, invariably fatal neurological disease that attacks the nerve cells responsible for controlling voluntary muscles. Amyotrophic late...

Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus. The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the...

Anal cancer is a disease in which malignant (cancer) cells form in the tissues of the anus. The anus is the end of the large intestine, below the rectum, through which stool (solid waste) leaves the body. The anus is formed partly from the...

Ankylosing spondylitis facts Ankylosing spondylitis belongs to a group of arthritis conditions that tend to cause chronic inflammation of the spine (spondyloarthropathies). Ankylosing spondylitis affects males two to three...

Jejunal Atresia is a rare genetic disorder. Patients with this disorder are born with a partial absence of the fold of the stomach membrane that connects the small intestine to the back wall of the abdomen. As a result, one of the three portions o...

Argininosuccinic aciduria is a rare inherited disorder characterized by deficiency or lack of the enzyme argininosuccinate lyase (ASL). Argininosuccinate lyase is one of six enzymes that play a role in the breakdown and removal of nitrogen from th...

Polymyalgia rheumatica is a rare inflammatory disease characterized by muscle pain (myalgia), stiffness, and additional generalized systemic symptoms such as fatigue, low-grade fever, and/or a general feeling of ill health (malaise). Polymyalgia r...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

What is the definition of asbestos? Asbestos is a family of naturally occurring silica compounds (similar to, but not the same as, the silica of window glass and computer chips). These substances form fibers with varying shapes and sizes a...

A disorder in which a person's airways become inflamed, constrict, and bulge, as well as cre...

Athlete's foot, also known as tinea pedis, is a common fungal infection that affects the skin on the feet. It is caused by various types of fungi, most commonly Trichophyton rubrum. Athlete's foot is highly contagious and can be spread through dir...

Atopic dermatitis facts Atopic dermatitis is a type of eczema. The disease may be inherited and genetically determined. The patient's skin may be "super sensitive" to many irritants. Dry, scaly patches ...

Atrial fibrillation (A-fib) is an irregular and often very rapid heart rhythm (arrhythmia) that can lead to blood clots in the heart. A-fib increases the risk of stroke, heart failure and other he...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Jervell and Lange-Nielsen syndrome (JLNS) is a rare inherited disorder characterized by deafness present at birth (congenital) occurring in association with abnormalities affecting the electrical system of the heart. The severity of cardiac sympto...

Machado-Joseph Disease (MJD-III), also called spinocerebellar ataxia type III, is a rare, inherited, ataxia (lack of muscular control) affecting the central nervous system and characterized by the slow degeneration of particular areas of the brain...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Bacterial vaginosis is an abnormal vaginal condition that is characterized by vaginal discharge and results from an overgrowth of atypical bacteria in the vagina. Bacterial vaginosis is not dangerous, but it can cause disturbing sym...

Bacterial vaginosis (BV) is a common vaginal infection caused by an imbalance of bacteria in the vagina. Normally, the vagina contains a balance of good and harmful bacteria. However, when the harmful bacteria outnumber the good bacteria, it can l...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Balantidiasis is a rare intestinal infection caused by the bacterium, Balantidium coli, a single celled parasite (ciliate protozoan) that frequently infects pigs but on occasion (rarely) infects humans. Some infected people may have no symptoms or...

Batten Turner Type Congenital Myopathy is an extremely rare, inherited muscle disease (myopathy) and is characterized by the lack of muscle tone or floppiness at birth (congenital hypotonia). The symptoms of Batten Turner Type Congenital Myopathy ...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

Bile duct cancer, also called cholangiocarcinoma, is when unusual cells grow out of control inside your bile ducts. Those are thin tubes about 4 to 5 inches long that move a fluid called bile from your liver to your gallbladder and small intestine...

Blepharitis is an inflammation of the eyelids. It is a common condition that can cause redness, itching, burning, and a gritty sensation in the eyes. It can also cause the eyelids to become swollen, crusty, and flaky. Blepharitis is usually caused...

Benign essential blepharospasm (BEB) is a rare neurological disorder in which affected individuals experience involuntary muscle spasms and contractions of the muscles around the eyes. These spasms come and go (intermittent). Symptoms may begin as...

Bloom syndrome is a rare genetic disorder characterized by short stature; increased sensitivity to light (photosensitivity); multiple small dilated blood vessels on the face (facial telangiectasia), often resembling a butterfly in shape; immune de...

Bocavirus is a virus that causes the common cold and other respiratory infections. Cold, fever, runny nose, and cough are the most common symptoms. It can also cause gastroenteritis, or stomach flu, which can cause severe stomach and intestine irr...

Boil  A boil is a painful, pus-filled bump under your skin — the result of a bacterial infection of one or more hair follicles. Carbuncle  A carbuncle is a cluster of boils — painful, pus-filled bumps ...

Branchio-oto-renal (BOR) syndrome is a rare disorder inherited as an autosomal dominant genetic trait. This disorder is characterized by pits or ear tags in front of the outer ear, abnormal passages from the throat to the outside surface of the ne...

Breast cancer is the most common cancer in pregnant women and tends to affect women in their mid-30s. Although only about 1 in every 1,000 pregnant women get breast cancer, the disease can be devastating to both the mother and her child -- so it i...

Introduction to Breast Cancer Recurrence Breast cancer can recur at any time, but most recurrences occur in the first three to five years after initial treatment. Breast cancer can come back as a local recurrence (in the treated breast or ...

Introduction to Breast Cancer Recurrence Breast cancer can recur at any time, but most recurrences occur in the first three to five years after initial treatment. Breast cancer can come back as a local recurrence (in the treated breast or ...

Facing a breast cancer diagnosis can be overwhelming. Your stress levels may skyrocket. You may worry about finances. And you may be asking yourself difficult questions, such as whether to write a living will. Education and supportive care can hel...

Facing a breast cancer diagnosis can be overwhelming. Your stress levels may skyrocket. You may worry about finances. And you may be asking yourself difficult questions, such as whether to write a living will. Education and supportive care can hel...

Bronchitis is an infection that causes irritation and inflammation in the lungs' major airways (bronchi). Bronchitis is divided into two types: acute and chronic. Chronic bronchitis is a long-term condition that can reoccur. Long-term stress, such...

Bronchitis is an infection that affects the lungs' major airways (bronchi), causing irritation and inflammation. Bronchitis can be classified into two types: acute and long-term. Chronic bronchitis is a long-term problem that can come back. It is usu...

Bullous pemphigoid is an uncommon skin disease characterized by tense blisters on the surface of the skin. Occasionally, the inner lining tissue of the mouth, nasal passages, or conjunctivae of the eyes (mucous membrane tissue) can be involved. Th...

Clubfoot is a general term used to describe a group of deformities of the ankles and/or feet that are usually present at birth (congenital). The defect may be mild or severe and may affect one or both of the ankles and/or feet. Different forms of ...

Campomelic dysplasia is a severe disorder that affects the development of the skeleton and reproductive system. This condition is often life-threatening in the newborn period. The term "campomelic" comes from the Greek words for "bent limb." Affec...

Campomelic syndrome is a rare congenital disorder in which multiple anomalies are present. It is characterized by bowing and angular shape of the long bones of the legs, especially the tibia; multiple minor anomalies of the face; cleft palate; oth...

Camptomelic syndrome is a rare congenital disorder in which multiple anomalies are present. It is characterized by bowing and angular shape of the long bones of the legs, especially the tibia; multiple minor anomalies of the face; cleft palate; ot...

Endometrial cancer Open pop-up dialog box Close Endometrial cancer Endometrial cancer Endometrial cancer begins in the lining (endometrium) of the uterus. Endometrial cancer is a type of cancer that begins in the uterus. The uterus...

Endometrial cancer begins in the lining (endometrium) of the uterus. Endometrial cancer is a type of cancer that begins in the uterus. The uterus is the hollow, pear-shaped pelvic organ where fetal development occurs. Endometrial c...

Pinta is a rare infectious tropical disease affecting the skin that is caused by the bacterium Treponema carateum, which is transmitted by direct, nonsexual contact. Pinta progresses through three distinct stages, which are characterized by variou...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

Roussy-Levy Syndrome, also known as hereditary areflexic dystasia, is a rare genetic neuromuscular disorder that typically becomes apparent during early childhood. The disorder is characterized by incoordination, poor judgment of movements (sensor...

Hajdu-Cheney syndrome (HCS) is a rare, heritable disorder of connective tissue; only about 50 cases have been reported in the medical literature. The breakdown of bone (osteolysis), especially the outermost bones of the fingers and toes (acroosteo...

Chickenpox, also known as varicella, is a highly contagious viral infection caused by the varicella-zoster virus. It is characterized by a red, itchy rash that usually starts on the face, chest, and back and then spreads to the rest of the body. O...

Chilblains (CHILL-blayns) are the painful inflammation of small blood vessels in your skin that occur in response to repeated exposure to cold but not freezing air. Also known as pernio, chilblains can cause itching, red patches, swelling and blis...

Duchenne muscular dystrophy (DMD) is a rare muscle disorder but it is one of the most frequent genetic conditions affecting approximately 1 in 3,500 male births worldwide. It is usually recognized between three and six years of age. DMD is charact...

An epidemic is defined as occurring when "new cases of a certain disease, in a given human population during a given time period, substantially exceed what is expected based upon recent experience." Pediatric obesity has reached epidemic proportio...

Chronic Bronchitis is a type of COPD (chronic obstructive pulmonary disease). COPD is a lung infection and disease that can make breathing difficult and progressively worsen over time. Other than COPD, the most common type of COPD is emphysema. Th...

Cleidocranial dysplasia is a rare skeletal dysplasia characterized by short stature, distinctive facial features and narrow, sloping shoulders caused by defective or absent collarbones (clavicles). Major symptoms may include premature closing of t...

General DiscussionWildervanck syndrome, also known as cervicooculoacoustic syndrome, is a rare genetic disorder that primarily affects females. The disorder is characterized by a skeletal condition known as Klippel-Feil syndrome (KFS); ab...

Haim-Munk syndrome is a rare genetic disorder characterized by the development of red, scaly thickened patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis), frequent pus-producing (pyogenic) skin infections...

Coffin-Siris syndrome is a rare genetic disorder that may be evident at birth (congenital). The disorder may be characterized by feeding difficulties and frequent respiratory infections during infancy, diminished muscle tone (hypotonia), abnormal ...

Compartment syndrome describes increased pressure within a muscle compartment of the arm or leg. It is most often due to injury, such as fracture, that causes bleeding in a muscle, which then causes increased pressure in the muscle. This pressure ...

What are congenital heart defects? Congenital (kon-JEN-ih-tal) heart defects are problems with the heart's structure that are present at birth. These defects can involve: The interior walls of the heart The valves ...

Conjunctivitis, commonly known as pink eye, is an inflammation of the conjunctiva, the thin, transparent membrane that lines the inner surface of the eyelid and covers the white part of the eye. It is usually caused by a bacterial or viral infecti...

Mixed connective tissue disease facts Connective tissues are the framework of the cells of the body. Mixed connective tissue disease is an "overlap" combination of connective tissue diseases. Diagnosis of mixed c...

Contact dermatitis facts Contact dermatitis is a rash that occurs at the site of exposure to a substance capable of producing an allegic or irritant skin response. Contact dermatitis can be caused by noxious, irritating su...

Contact lens-related eye infections are infections of the eye caused by the improper use of contact lenses. These infections can range from mild to severe and can cause a variety of symptoms, including redness, itching, burning, and blurred vision...

COPD is a chronic lung disease that results in obstructed airflow from the lungs. Asthmatics have difficulty breathing, cough, cough up mucus (sputum), and wheeze. It is most commonly caused by long-term exposure to irritating particles or gases, ...

COPD is a long-term lung disease that causes blocked airflow from the lungs. People who have asthma have trouble breathing, cough, cough up mucus (sputum), and wheeze. It is most often caused by exposure to irritating particles or gases over a long p...

Corneal abrasion is a condition in which the outer layer of the cornea (the clear, dome-shaped surface that covers the front of the eye) is scratched or scraped. It is a common eye injury that can cause pain, redness, tearing, and light sensitivit...

Corneal dystrophies are a group of inherited eye disorders that cause progressive changes to the cornea, the clear outer layer of the eye. These disorders can cause vision loss and other eye problems. Symptoms vary depending on the type of corneal...

Corneal laceration is a tear or cut in the cornea, the clear, dome-shaped surface that covers the front of the eye. It is usually caused by a sharp object, such as a fingernail, a piece of metal, or a tree branch. Corneal lacerations can cause pai...

A corneal ulcer is an open sore on the cornea, the clear dome-shaped surface that covers the front of the eye. It is usually caused by an infection, such as bacterial, viral, or fungal, or by an injury to the eye. Symptoms of a corneal ulcer inclu...

Cradle cap causes crusty or oily scaly patches on a baby's scalp. The condition isn't painful or itchy. But it can cause thick white or yellow scales that aren't easy to remove. Cradle cap usually clears up on its own in a few months. Home...

Freeman-Sheldon syndrome is a rare inherited disorder characterized by multiple contractures (i.e., restricted movement around two or more body areas) at birth (congenital), abnormalities of the head and face (craniofacial) area, defects of the ha...

Chromosome 22q11.2 deletion syndrome is associated with a range of problems including: congenital heart disease, palate abnormalities, immune system dysfunction including autoimmune disease, low calcium (hypocalcemia) and other endocrine abnormali...

Craniofrontonasal dysplasia is a very rare inherited disorder characterized by abnormalities of the head and face (craniofacial area), hands and feet, and certain skeletal bones. Major symptoms of this disorder may include widely spaced eyes (ocul...

Creutzfeldt-Jakob disease (CJD) is a rare, degenerative, invariably fatal brain disorder. It affects about one person in every one million people per year worldwide; in the United States there are about 200 cases per year. CJD usually appears in l...

Adenoid cystic carcinoma (ACC) is a relatively rare form of cancer that most commonly develops in the salivary glands or other regions of the head and neck. In some cases, ACC may arise in other primary sites, such as the skin; the breast; the nec...

Gianotti-Crosti Syndrome is a rare skin disease affecting children between the ages of nine months and nine years. Major symptoms may include blisters on the skin of the legs, buttocks and arms. The disorder is usually preceded by a viral infectio...

Mixed cryoglobulinemia is a rare disorder characterized by the presence of cryoglobulins in the blood. Cryoglobulins are abnormal proteins that thicken and clump together at cold temperatures, usually below 98.6 degrees Fahrenheit (the average hum...

An interstitial lung disease occurs when there is cryptogenic fibrous alveolitis in the lungs (or ILD for short). They have an impact on the tissues that support the air sacs in the lungs, making it difficult for them to take in as much air as the...

Cutis laxa is rarely encountered and may occur in several inherited (congenital) forms or come about in the course of another disorder (acquired). It is a connective tissue disorder characterized by skin that is loose (lax), hanging, wrinkled, and...

De Barsy syndrome is a rare, autosomal recessive genetic disorder, the main characteristics of which are a prematurely aged-looking face (progeria), cloudy corneas, short stature, and mental retardation. The condition is expressed in variable pres...

Common Variable Immune Deficiency (CVID) is a type of primary immunodeficiency, which is defined as an immune system dysfunction typically caused by a mutation in a gene or genes. The World Health Organization (WHO) recognizes more than 150 primar...

Autosomal dominant interstitial kidney disease describes a group of diseases affecting solely the proper function of the kidney and having the following characteristics: They are inherited in an autosomal dominant manner; kidney disease develops, ...

Autosomal dominant interstitial kidney disease describes a group of diseases affecting solely the proper function of the kidney and having the following characteristics: They are inherited in an autosomal dominant manner; kidney disease develops, ...

A cystocele occurs when the wall between a woman's bladder and her vagina weakens and allows the bladder to droop into the vagina. Symptoms of a cystocele include urine leakage and incomplete emptying of the bladder. Cause...

Cyst facts Cysts are closed sac-like or capsule structures that may be filled with semisolid material, gaseous material, or liquid. There are several causes of cysts, including genetic, infectious, and other causes that resu...

Autosomal dominant interstitial kidney disease describes a group of diseases affecting solely the proper function of the kidney and having the following characteristics: They are inherited in an autosomal dominant manner; kidney disease develops, ...

General DiscussionThe word "neurasthenia" is a term that has fallen into disuse among psychiatrists in the United States and Australia. It remains in use in the United Kingdom. Where it is used, it covers a wide spectrum of symptoms inclu...

Keratosis follicularis, also known as Darier disease, is a rare, genetic skin disorder. Affected individuals develop skin lesions that consist of thickened, rough bumps (papules) or plaques that may also be greasy or have a brown or yellow crust. ...

Microvillus inclusion disease is an extremely rare inherited intestinal disorder (enteropathy) that is typically apparent within hours or days after birth. The disorder is characterized by chronic, severe, watery diarrhea and insufficient absorpti...

De Barsy syndrome is a rare, autosomal recessive genetic disorder, the main characteristics of which are a prematurely aged-looking face (progeria), cloudy corneas, short stature, and mental retardation. The condition is expressed in variable pres...

De Sanctis-Cacchione syndrome is an extremely rare disorder characterized by the skin and eye symptoms of xeroderma pigmentosum (XP) occurring in association with neurological abnormalities, mental retardation, unusually short stature (dwarfism), ...

General DiscussionJervell and Lange-Nielsen syndrome (JLNS) is a rare inherited disorder characterized by deafness present at birth (congenital) occurring in association with abnormalities affecting the electrical system of the heart. The...

Peeling skin syndrome is a rare inherited skin disorder characterized by painless, continual, spontaneous skin peeling (exfoliation). Other findings may include blistering and/or reddening of the skin (erythema) and itching (pruritus). Peeling ski...

Degenerative disc disease and sciatica facts The discs of the spine serve as "cushions" between each vertebral segment. The discs are designed somewhat like a jelly donut. Degeneration (deterioration) of the disc...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Degos disease is an extremely rare disorder in which small and medium sized arteries become blocked (occlusive arteriopathy), restricting the flow of blood to affected areas. Degos disease usually causes characteristic skin lesions that may last f...

Determining hearing loss in children facts Children can be tested for hearing loss at any age. There are several risk factors associated with hearing loss, including ear infections, prematurity, diseases, and syndromes....

Diabetes facts Diabetes is a chronic condition associated with abnormally high levels of sugar (glucose) in the blood. Insulin produced by the pancreas lowers blood glucose. Absence or insufficient production of ...

What is the difference between diabetes insipidus and diabetes mellitus Diabetes insipidus should not be confused with diabetes mellitus (DM), which results from insulin deficiency or resistance leading to high blood glucose, also called b...

What is the difference between diabetes insipidus and diabetes mellitus Diabetes insipidus should not be confused with diabetes mellitus (DM), which results from insulin deficiency or resistance leading to high blood glucose, also called b...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

Urine tests for diabetes facts Urine tests may be done in people with diabetes to evaluate severe hyperglycemia (severe high blood sugar) by looking for ketones in the urine. Ketones are a metabolic product produced when fat...

Urine tests for diabetes facts Urine tests may be done in people with diabetes to evaluate severe hyperglycemia (severe high blood sugar) by looking for ketones in the urine. Ketones are a metabolic product produced when fat...

Type 2 diabetes is an impairment in the way the body regulates and uses sugar (g...

Achard-Thiers syndrome is a rare disorder that occurs primarily in postmenopausal women and is characterized by type 2 (insulin-resistant) diabetes mellitus and signs of androgen excess. The exact cause of this syndrome is unknown....

Diabetic ketoacidosis is a serious complication of diabetes that occurs when you...

Diabetic ketoacidosis is a serious complication of diabetes that occurs when you...

Diastrophic dysplasia, which is also known as disastrophic dwarfism, is a rare disorder that is present at birth (congenital). The range and severity of associated symptoms and physical findings may vary greatly from case to case. However, the dis...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

Diphtheria is a serious bacterial infection that usually affects the mucous membranes of the throat and nose. It is caused by the bacterium Corynebacterium diphtheriae and is spread through respiratory droplets or direct contact with an infected p...

Dyggve-Melchior-Clausen (DMC) syndrome is a rare, progressive genetic disorder characterized by abnormal skeletal development, microcephaly and intellectual disability. The condition was first reported by Dyggve, Melchior and Clausen in 1962 in th...

Dyggve-Melchior-Clausen (DMC) syndrome is a rare, progressive genetic disorder characterized by abnormal skeletal development, microcephaly and intellectual disability. The condition was first reported by Dyggve, Melchior and Clausen in 1962 in th...

Sjogren-Larsson syndrome is an inherited disorder characterized by scaling skin (ichthyosis), mental retardation, speech abnormalities, and spasticity. Affected infants develop various degrees of reddened skin with fine scales soon after birth. Af...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Ichthyosis hystrix, Curth-Macklin type is a rare inherited skin disorder. It is characterized by scaling skin (ichthyosis) ranging from mild to severe. The patches of scaly, thickened skin range from spotty to severe, and may appear on almost any ...

Chanarin Dorfman syndrome is a rare hereditary disorder of fat (lipid) metabolism. It is characterized by scaly skin (ichthyosis), degeneration of the muscles (myopathy), and abnormal white blood cells with small spaces (vacuoles) filled with fat ...

Dry eye is a condition in which the eyes do not produce enough tears or the tears evaporate too quickly. This can cause irritation, redness, and a feeling of dryness in the eyes. Dry eye can be caused by a variety of factors, including environment...

Dry skin facts Dry skin is a very common condition that causes small fine flakes and dry patches. Itching is one of the most common symptoms of dry skin. Scratching may be hard to resist. Dry skin is mo...

Frey syndrome is a rare disorder that most often occurs as a result of surgery in the area near the parotid glands. The parotid glands are the largest salivary glands in the body located just below the ears on either side of the face. The main sym...

Dupuytren's contracture facts A Dupuytren's contracture is a localized scar tissue formation in the palm. The precise cause of a Dupuytren's contracture is not known. A Dupuytren's contracture is sometimes inheri...

Keratosis follicularis, also known as Darier disease, is a rare, genetic skin disorder. Affected individuals develop skin lesions that consist of thickened, rough bumps (papules) or plaques that may also be greasy or have a brown or yellow crust. ...

Dysplasia epiphysealis hemimelica, also known as Trevor disease, is a rare skeletal developmental disorder of childhood. It is characterized by an overgrowth of cartilage on the ends (epiphyses) of the long bones of the arms and legs and the bones...

An ectopic pregnancy is a pregnancy located outside the inner lining of the uterus. Risk factors for ectopic pregnancy include previous ectopic pregnancies and conditions (surgery, infection) that disrupt the normal anatomy of the F...

General DiscussionEisenmenger syndrome is a rare progressive heart condition that develops in some individuals with structural malformations of the heart that are present from birth (congenital heart defects). The disorder is characterize...

Williams syndrome, also known as Williams-Beuren syndrome, is a rare genetic disorder characterized by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and dist...

Pinta is a rare infectious tropical disease affecting the skin that is caused by the bacterium Treponema carateum, which is transmitted by direct, nonsexual contact. Pinta progresses through three distinct stages, which are characterized by variou...

Emphysema is a lung disease that usually develops after a long period of smoking. Chronic bronchitis and emphysema are both types of lung disorders that are classified as chronic obstructive pulmonary disease (COPD) (COPD). COPD is an umbrella ter...

Encephaloceles are rare birth defects associated with skull defects characterized by partial lacking of bone fusion leaving a gap through which a portion of the brain sticks out (protrudes). In some cases, cerebrospinal fluid or the membranes that...

Atrioventricular septal defect (ASVD) is a general term for a group of rare heart defects that are present at birth (congenital). Infants with ASVDs have improperly developed atrial and ventricular septa and adjoining valves. The norma...

Endocardial fibroelastosis (EFE) is a rare heart disorder that affects infants and children. It is characterized by a thickening within the muscular lining of the heart chambers due to an increase in the amount of supporting connective tissue (ine...

Carcinoid syndrome is a disease consisting of a combination of symptoms, physical manifestations, and abnormal laboratory findings. Carcinoid syndrome is seen in individuals who have an underlying carcinoid tumour with spread to the liver. Carcino...

Epidermolysis bullosa (ep-ih-dur-MOL-uh-sis buhl-LOE-sah) is a group of rare diseases that cause fragile, blistering skin. The blisters may appear in response to minor injury, even from heat, rubbing, scratching or adhesive tape. In severe cases, ...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Epidermolytic ichthyosis (EI) specifically refers to a hereditary skin disorder that is characterized by varying degrees of blistering and subsequent reactive scaling of the skin. The underlying histopathology shows mid-epidermal splitting and hyp...

Until recently the relationship of Stevens-Johnson syndrome to other severe blistering disorders was a matter of some debate. Now a consensus seems to be evolving that describes SJS as a rare disorder involving lesions of the mucous membranes alon...

Erythema nodosum is a type of skin inflammation that is located in a certain portion of the fatty layer of skin. Erythema nodosum (also called EN) results in reddish, painful, tender lumps most commonly located in the front of the legs below the k...

Polycythemia vera is a rare, chronic disorder involving the overproduction of blood cells in the bone marrow (myeloproliferation). The overproduction of red blood cells is most dramatic, but the production of white blood cells and platelets are al...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Erythropoietic protoporphyria (EPP) is a rare inherited metabolic disorder characterized by a deficiency of the enzyme ferrochelatase (FECH). Due to abnormally low levels of this enzyme, excessive amounts of protoporphyrin accumulate in the bone m...

Achalasia is a rare disorder of the esophagus, the tube that carries food from the throat to the stomach. It is characterized by enlargement of the esophagus, impaired ability to push food down toward the stomach (peristalsis), and failure of the ...

Cryptococcosis is caused by a fungus known as Cryptococcosis neoformans. The infection may be spread to humans through contact with pigeon droppings or unwashed raw fruit. Contact with an infected individual may also spread the infection. Individu...

Extrinsic Allergic Pneumonia, also known as Allergic Interstitial Pneumonitis and Hypersensitivity Pneumonitis, is an inflammatory syndrome that affects the lungs. Extrinsic: the origin is an external matter - an antigen. Allergic: The cau...

Eye allergies, also known as allergic conjunctivitis, are a type of allergic reaction that affects the eyes. Symptoms of eye allergies include redness, itching, burning, tearing, and swelling of the eyes. Eye allergies are usually caused by airbor...

Cardiofaciocutaneous (CFC) syndrome is one of the RASopathies and is a rare genetic disorder is typically characterized by unusually sparse, brittle, curly hair; large head (macrocephaly); a prominent forehead and abnormal narrowing of the sides o...

Aarskog syndrome is an extremely rare genetic disorder marked by stunted growth that may not become obvious until the child is about three years of age, broad facial abnormalities, musculoskeletal and genital anomalies, and mild intellectual disab...

Facioscapulohumeral muscular dystrophy (FSHD), also known as Landouzy-Dejerine muscular dystrophy, is a neuromuscular disorder. Symptom onset usually occurs in adolescence or early adulthood; however, less commonly, symptoms may become apparent as...

Peeling skin syndrome is a rare inherited skin disorder characterized by painless, continual, spontaneous skin peeling (exfoliation). Other findings may include blistering and/or reddening of the skin (erythema) and itching (pruritus). Peeling ski...

Tangier Disease is an inherited blood disorder involving decreased concentrations of fat compounds in the blood called high-density lipoproteins (sometimes called "good cholesterol"). Large amounts of these compounds may accumulate in certain orga...

Congenital fiber type disproportion (CFTD) is a rare genetic muscle disease that is usually apparent at birth (congenital myopathy). It belongs to a group of muscle conditions called the congenital myopathies that tend to affect people in a simila...

Endomyocardial fibrosis (EMF) is a progressive disease of unknown origin (idiopathic) that may seriously affect the heart. Its most obvious feature is a gross change in the makeup of the lining of the heart cavities (the endocardium) of one or bot...

General DiscussionWeil syndrome, a rare infectious disorder, is a severe form of the bacterial infection caused by Leptospira bacteria known as leptospirosis. Weil syndrome is characterized by dysfunction of the kidneys and liver, abnorma...

Fitz-Hugh-Curtis syndrome is a rare disorder that occurs almost exclusively in women. It is characterized by inflammation of the membrane lining the stomach (peritoneum) and the tissues surrounding the liver (perihepatitis). The muscle that separa...

You have flatfeet when the arches on the inside of your feet are flattened, allowing the entire soles of your feet to touch the floor when you stand up. A common and usually painless condition, flatfeet can occur when the arches don't deve...

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is a rare skin disorder that can also affect bone and eye development. If is a type of ectodermal dysplasia, a group of heritable disorders causing the hair, teeth, nails, and glands to ...

Focal dermal hypoplasia (FDH), also known as Goltz syndrome, is a rare skin disorder that can also affect bone and eye development. If is a type of ectodermal dysplasia, a group of heritable disorders causing the hair, teeth, nails, and glands to ...

Formaldehyde Poisoning is a disorder brought about by breathing the fumes of formaldehyde. This can occur while working directly with formaldehyde, or using equipment cleaned with formaldehyde. Major symptoms may include eye, nose, and throat irri...

Formaldehyde is a transitional molecule that participates in a wide range of biological activities. It can be found in a variety of everyday items, including meals. It's also used in medicine to treat a variety of ailments. Formalin is a 40 percen...

Fountain syndrome is an extremely rare inherited disorder that is characterized by mental retardation; abnormal swelling of the cheeks and lips due to the excessive accumulation of body fluids under the skin (subcutaneous) of the face (edema); ske...

Fox-Fordyce disease is a rare skin disorder that primarily affects women. The disorder is characterized by intense itching especially in the underarm area, the pubic area and around the nipples. In Fox-Fordyce disease abnormalities affecting the a...

Treacher Collins syndrome (TCS) is a rare genetic disorder characterized by distinctive abnormalities of the head and face area resulting from underdevelopment (hypoplasia) of certain facial structures including the jaw, cheekbones and nearby stru...

Freeman-Sheldon syndrome is a rare inherited disorder characterized by multiple contractures (i.e., restricted movement around two or more body areas) at birth (congenital), abnormalities of the head and face (craniofacial) area, defects of the ha...

Frozen shoulder Frozen shoulder occurs when the connective tissue enclosing the joint becomes thickened and tight. Frozen shoulder, also known as adhesive capsulitis, is a condition characterized by stiffness and pain in your shoul...

Fungal keratitis is an infection of the cornea, the clear outer layer of the eye, caused by a fungus. It is a rare but serious condition that can cause vision loss if not treated promptly. Symptoms of fungal keratitis include redness, pain, blurre...

Galactosemia is a rare, hereditary disorder of carbohydrate metabolism that affects the body's ability to convert galactose (a sugar contained in milk, including human mother's milk) to glucose (a different type of sugar). Galactose is converted t...

Hypogammaglobulinemia is a problem with the immune system that prevents it from making enough antibodies called immunoglobulins. Antibodies are proteins that help your body recognize and fight off foreign invaders like bacteria, viruses, and fungi...

Gangrene facts Gangrene refers to dead or dying body tissue(s) that occur because of inadequate blood supply. There are two major types of gangrene, wet gangrene and dry gangrene. Dry gangrene can result from con...

Though ulcers often heal on their own, you shouldn't ignore their warning signs. If not properly treated, ulcers can lead to serious health problems, including: Bleeding Perforation (a hole through the wall of the stomach)...

Gastritis is inflammation of the lining of the stomach. Unfortunately, the term "gastritis" has been misused to include many different upper abdominal problems, but true gastritis refers to the stomach lining (gastric mucosa) that is inflamed. All...

Eosinophilic gastroenteritis is a rare digestive disease characterized by the triad of eosinophilic infiltration of segments of the gastrointestinal tract, abnormalities of gastrointestinal function (varying from dyspepsia and obstruction to diarr...

Mallory-Weiss syndrome refers to a tear or laceration of the mucous membrane, most commonly at the point where the esophagus and the stomach meet (gastroesophageal junction). Such a tear may result in severe bleeding from the gastrointestinal trac...

Genital herpes, also known as herpes simplex virus type 2 (HSV-2), is a sexually transmitted infection that causes painful sores and blisters on the genital area. It is a chronic condition that can flare up periodically, causing symptoms such as i...

Genital herpes is a sexually transmitted disease caused by herpes simplex virus (HSV). HSV causes genital herpes by entering the skin or mucous membranes through microscopic breaks in the skin and mucous membranes. Genital...

Genital warts are a sexually transmitted infection caused by the human papillomavirus (HPV). They are small, flesh-colored bumps or growths that appear on or around the genital area. Genital warts can be spread through sexual contact and are highl...

Genital warts (HPV) facts Genital warts are caused by infection with a subgroup of the human papillomaviruses (HPVs). Another subgroup of the HPVs that infect the anogenital tract can lead to precancerous changes in the ut...

Giant Papillary Conjunctivitis (GPC) is an inflammatory condition of the eye that affects the inner surface of the eyelids. It is caused by an allergic reaction to contact lenses, foreign bodies, or other irritants. Symptoms include itching, redne...

Progeria, or Hutchinson-Gilford progeria syndrome (HGPS), is a rare, fatal, genetic condition of childhood with striking features resembling premature aging. Children with progeria usually have a normal appearance in early infancy. At approximatel...

Erythrokeratodermia with ataxia (EKDA) is a hereditary disorder of the skin and nervous system (neurocutaneous syndrome) characterized by groups of hard, red plaques that develop during infancy and childhood. When these skin lesions heal, the diso...

Pierre Robin sequence is characterized by an unusually small lower jaw (micrognathia) and downward displacement of the tongue (glossoptosis). Some infants also have an abnormal opening in the roof of the mouth (cleft palate); both the soft and har...

Andersen disease belongs to a group of rare genetic disorders of glycogen metabolism, known as glycogen storage diseases. Glycogen is a complex carbohydrate that is converted into the simple sugar glucose for the body's use as energy. Glycogen sto...

Gonorrhea is a sexually transmitted infection (STI) caused by the bacterium Neisseria gonorrhoeae. It can infect both men and women and is most commonly spread through unprotected sexual contact. Symptoms of gonorrhea can include painful urination...

Gonorrhea is a bacterial infection that is transmitted during sexual activity. Gonorrhea is not transmitted from toilet seats. Women infected with gonorrhea may not have any symptoms. Gonorrhea is treated with an...

Acquired agranulocytosis is a rare, drug-induced blood disorder that is characterized by a severe reduction in the number of white blood cells (granulocytes) in the circulating blood. The name granulocyte refers to grain-like bodies within the cel...

Group B Strejsonococcus (GBS) is a type of bacteria that is commonly found in the gastrointestinal tract, vagina, and rectum of healthy individuals. While GBS is usually harmless in healthy adults, it can cause serious infections in newborn babies...

Growth hormone insensitivity (GHI) is a group of extremely rare genetic disorders in which the body is unable to use the growth hormone that it produces. GHI can be caused by mutations in the growth hormone receptor (GHR) gene or mutations in gene...

Lichen sclerosus is a chronic skin disorder that most commonly affects post-menopausal women. However, it is sometimes identified among pre-menopausal women, and, even more rarely, among males. When found in males, the disease is known as balaniti...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Lichen sclerosus is a chronic skin disorder that most commonly affects post-menopausal women. However, it is sometimes identified among pre-menopausal women, and, even more rarely, among males. When found in males, the disease is known as balaniti...

Gottron syndrome (GS) is an extremely rare inherited disorder characterized by the appearance of premature aging (progeria), especially in the form of unusually fragile, thin skin on the hands and feet (distal extremities). GS is described as a mi...

Congenital central hypoventilation syndrome (CCHS) is a rare disorder of respiratory control with autonomic nervous system dysregulation (ANSD). The autonomic nervous system is the portion of the nervous system that controls or regulates certain i...

Haemophilus influenzae type b (Hib) is a type of bacteria that can cause serious infections, particularly in young children. It can lead to illnesses such as meningitis, pneumonia, and epiglottitis. The Hib vaccine is highly effective in preventin...

Histidinemia is a rare hereditary metabolic disorder characterized by a deficiency of the enzyme histidase, which is necessary for the metabolism of the amino acid histidine. The concentration of histidine is elevated in the blood. Excessive amoun...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Paroxysmal cold hemoglobinuria (PCH) is a rare type of anemia characterized by the premature destruction of healthy red blood cells by autoantibodies. The disorder is classified as an autoimmune hemolytic anemia (AIHA), an uncommon group of disord...

Chromosome 10, monosomy 10p is a rare chromosomal disorder in which the end (distal) portion of the short arm (p) of chromosome 10 is missing (deleted or monosomic). The range and severity of symptoms and findings may be variable, depending upon t...

Hashimoto's thyroiditis is also known as Chronic Lymphocytic Thyroiditis, Hashimoto's Thyroiditis, and Chronic Autoimmune Thyroiditis. The thyroid gland gradually stops producing enough hormones to keep the body running normally as a result of Has...

Head lice, also known as pediculosis, are tiny parasitic insects that live on the scalp and feed on human blood. They are common among school-aged children and can easily spread through close personal contact or by sharing personal items such as h...

Introduction to heart transplant The idea of replacing a bad organ with a good one has been documented in ancient mythology. The first real organ transplants were probably skin grafts that may have been done in India as early as the second...

Heat rash facts Heat rash occurs when the skin's sweat glands are blocked and the sweat produced cannot get to the surface of the skin to evaporate. This causes inflammation that results in a rash. Common symptoms of heat ...

Helicobacter pylori (H. pylori) facts Helicobacter pylori (H. pylori) is a bacterium that causes chronic inflammation in the stomach and is a common cause of ulcers worldwide H. pylori causes chronic inflammation (gastriti...

Hemolytic uremic syndrome (HUS) is a condition caused by the abnormal destruction of red blood cells. The damaged red blood cells clog the filtering system in the kidneys, which can lead to life-threatening kidney failure. HUS usually deve...

Herpes Simplex Virus (HSV) is a common viral infection that causes sores or blisters on the skin or mucous membranes. There are two types of HSV: HSV-1, which typically causes cold sores or fever blisters around the mouth, and HSV-2, which typical...

The esophagus connects the mouth and throat to the stomach. It passes through the chest cavity and enters the abdominal cavity through a hole in the diaphragm called the esophageal hiatus. The term hiatal hernia describes a condition where a part ...

Hiccup facts A hiccup is a sudden, involuntary contraction (spasm) of the diaphragm muscle. When the muscle spasms, the vocal cords snap shut, producing the hiccup sound. Common causes of hiccups include eating too quickly...

A hiccup is an involuntary spasmodic contraction of the muscle at the base of the lungs (diaphragm) followed by the rapid closure of the vocal cords. Usually, hiccups last for a few hours or, occasionally, a day or two. However, chronic hiccups ar...

Autosomal recessive hyper IgE syndrome (AR-HIES) is a very rare primary immunodeficiency disorder. Symptoms often become apparent at birth or early during infancy or childhood. The disorder is characterized by the triad of highly elevated levels o...

Von Hippel-Lindau syndrome (VHL) is an autosomal dominant genetic disorder characterized by the abnormal growth of blood vessels in certain parts of the body (angiomatosis). Very small blood vessels (capillaries) "knot" together to form benign gro...

Langerhans cell histiocytosis (LCH) is a spectrum of rare disorders characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the various tissues and organs of the body (lesions). The l...

Histoplasmosis is an infection caused by the fungus Histoplasma. The fungus can be found in the environment, particularly in soil with a high concentration of bird or bat droppings. Histoplasma is mostly found in the central and eastern United Sta...

Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop i...

Alkaptonuria is a rare genetic metabolic disorder characterized by the accumulation of homogentisic acid in the body. Affected individuals lack enough functional levels of an enzyme required to breakdown homogentisic acid. Affected individuals may...

Infant respiratory distress syndrome is a lung disorder that tends to affect premature infants. Major symptoms include difficulty in breathing and collapsed lungs, potentially requiring mechanical ventilation or positive end-expiratory pressure (P...

Williams syndrome, also known as Williams-Beuren syndrome, is a rare genetic disorder characterized by growth delays before and after birth (prenatal and postnatal growth retardation), short stature, a varying degree of mental deficiency, and dist...

Hyperlipoproteinemia type III, also known as dysbetalipoproteinemia or broad beta disease, is a rare genetic disorder characterized by improper breakdown (metabolism) of certain fatty materials known as lipids, specifically cholesterol and triglyc...

Familial lipoprotein lipase (LPL) deficiency is a rare genetic metabolic disorder characterized by a deficiency of the enzyme lipoprotein lipase. Deficiency of this enzyme prevents affected individuals from properly digesting certain fats and resu...

High blood sugar (hyperglycemia) affects people who have diabetes. Several facto...

Hypermobility syndrome facts The joint hypermobility syndrome is a condition that features joints that easily move beyond the normal range expected for a particular joint. Hypermobile joints tend to be inherited. ...

General DiscussionHypoplastic left heart syndrome is a term used to describe a group of closely related rare heart defects that are present at birth (congenital). The normal heart has four chambers. The two upper chambers, known as atria,...

Ichthyosis is a general term for a family of rare genetic skin diseases characterized by dry, thickened, scaling skin. The various forms are distinguished from one another by: 1) extent of the scaling and how widely and where the scaling is scatte...

Lamellar ichthyosis is a rare genetic skin disorder. In lamellar ichthyosis, the skin cells are produced at a normal rate, but they do not separate normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickl...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Harlequin ichthyosis is a rare genetic skin disorder. The newborn infant is covered with plates of thick skin that crack and split apart. The thick plates can pull at and distort facial features and can restrict breathing and eating. Harlequin inf...

Ichthyosis hystrix, Curth-Macklin type is a rare inherited skin disorder. It is characterized by scaling skin (ichthyosis) ranging from mild to severe. The patches of scaly, thickened skin range from spotty to severe, and may appear on almost any ...

Epidermal nevus syndromes (ENSs) are a group of rare complex disorders characterized by the presence of skin lesions known as epidermal nevi associated with additional extra-cutaneous abnormalities, most often affecting the brain, eye and skeletal...

Keratosis follicularis spinulosa decalvans (KFSD) is a rare, inherited, skin disorder that affects men predominately and is characterized by hardening of the skin (keratosis) in several parts of the body. Most frequently, the face, neck, and forea...

Sjogren-Larsson syndrome is an inherited disorder characterized by scaling skin (ichthyosis), mental retardation, speech abnormalities, and spasticity. Affected infants develop various degrees of reddened skin with fine scales soon after birth. Af...

Sjogren-Larsson syndrome is an inherited disorder characterized by scaling skin (ichthyosis), mental retardation, speech abnormalities, and spasticity. Affected infants develop various degrees of reddened skin with fine scales soon after birth. Af...

Ichthyosis vulgaris (ik-thee-O-sis vul-GAY-ris) is an inherited skin disorder in which dead skin cells accumulate in thick, dry scales on your skin's surface. The scales of ichthyosis vulgaris, sometimes called fish scale disease or fish s...

X-linked ichthyosis is a genetic skin disorder that affects males. It is an inborn error of metabolism characterized by a deficiency of the enzyme steroid sulfatase. Under normal conditions, this enzyme breaks down (metabolizes) cholesterol sulfat...

IgA nephropathy (nuh-FROP-uh-thee), also known as Berger's disease, is a kidney disease that occurs when an antibody called immunoglobulin A (IgA) lodges in your kidneys. This results in local inflammation that, over time, may hamper your kidneys'...

Hyper-IgM Syndrome (HIM) is a rare genetic (primary) immunodeficiency disorder that is typically inherited as an X-linked recessive genetic trait. Symptoms and physical findings associated with the disorder usually become apparent in the first or ...

Agammaglobulinemia is a group of inherited immune deficiencies characterized by a low concentration of antibodies in the blood due to the lack of particular lymphocytes in the blood and lymph. Antibodies are proteins (immunoglobulins, (IgM), (IgG)...

Impetigo facts Impetigo is a bacterial infection of the surface of the skin. Impetigo is more common in children than in adults. The two types of impetigo are non-bullous and bullous impetigo. Impetigo ...

Dyspepsia (indigestion) facts Dyspepsia is a functional disease in which the gastrointestinal organs, primarily the stomach and first part of the small intestine, function abnormally. It is a chronic disease in which the symptoms fl...

Apnea is a term used to describe the temporary absence of spontaneous breathing. Infantile apnea occurs in children under the age of one year. Apnea may occur because of neurological impairment of the respiratory rhythm or obstruction of air flow ...

West syndrome is a type of epilepsy characterized by spasms, abnormal brain wave patterns called hypsarrhythmia and sometimes mental retardation. The spasms that occur may range from violent jackknife or "salaam" movements where the whole body ben...

West syndrome is a type of epilepsy characterized by spasms, abnormal brain wave patterns called hypsarrhythmia and sometimes mental retardation. The spasms that occur may range from violent jackknife or "salaam" movements where the whole body ben...

Infant respiratory distress syndrome is a lung disorder that tends to affect premature infants. Major symptoms include difficulty in breathing and collapsed lungs, potentially requiring mechanical ventilation or positive end-expiratory pressure (P...

Apnea is a term used to describe the temporary absence of spontaneous breathing. Infantile apnea occurs in children under the age of one year. Apnea may occur because of neurological impairment of the respiratory rhythm or obstruction of air flow ...

The spinal muscular atrophies (SMAs), are characterized by degeneration of nerve cells (motor nuclei) within the lowest region of the brain (lower brainstem) and certain motor neurons in the spinal cord (anterior horn cells) leading to muscle weak...

The spinal muscular atrophies (SMAs), are characterized by degeneration of nerve cells (motor nuclei) within the lowest region of the brain (lower brainstem) and certain motor neurons in the spinal cord (anterior horn cells) leading to muscle weak...

Influenza, commonly known as the flu, is a contagious respiratory illness caused by influenza viruses. It can cause mild to severe illness and can sometimes lead to hospitalization or even death. Symptoms of the flu include fever, cough, sore thro...

Insulin is a hormone that is produced by the beta cells of the pancreas. These cells are scattered throughout the pancreas in small clusters known as the islets of Langerhans. The insulin produced is released into the blood stream and travels thro...

Intertrigo is a dermatitis that only affects skin folds. Intertrigo is caused when skin is irritated by friction, which is enhanced by moisture and heat. Risk factors for intertrigo include obesity, heat, and humidity....

Osteonecrosis, also known as avascular necrosis, is a disease resulting from the temporary or permanent loss of the blood supply to the bones. Without blood, the bone tissue dies and causes the bone to collapse. If the process involves the bones n...

Hypomelanosis of Ito is a rare condition characterized by distinctive skin changes, in which areas of the body lack skin color (hypopigmentation). These skin changes may present as patches, streaks or spiral-shaped (whorled) areas. In many cases, ...

wJansen type metaphyseal chondrodysplasia is an extremely rare progressive disorder in which portions of the bones of the arms and legs develop abnormally with unusual cartilage formations and subsequent abnormal bone formation at the large (bulbo...

Jarcho-Levin syndrome is a rare genetic disorder characterized by distinctive malformations of bones of the spinal column (vertebrae) and the ribs, respiratory insufficiency, and/or other abnormalities. Infants born with Jarcho-Levin syndrome have...

Jessner lymphocytic infiltrate of the skin is an uncommon disorder that is characterized by benign accumulations of lymph cells in the skin. These small lesions are solid, pink or red in color, and appear on the face, neck, and/or back. Skin surro...

Jock itch facts Jock itch is a very common groin rash. Roughly half of jock itch is due to fungus. The remainder is caused by moisture, irritation, and bacterial overgrowth. Symptoms and signs of jock itch includ...

Jock itch, also known as tinea cruris, is a fungal infection that affects the skin of the groin area. It is caused by a type of fungus called dermatophytes, which thrive in warm, moist environments. Jock itch is characterized by red, itchy, and so...

Joubert syndrome is an autosomal recessive genetic disorder that affects the area of the brain that controls balance and coordination. This condition is characterized by a specific finding on an MRI called a "molar tooth sign" in which the cerebel...

Joubert syndrome is an autosomal recessive genetic disorder that affects the area of the brain that controls balance and coordination. This condition is characterized by a specific finding on an MRI called a "molar tooth sign" in which the cerebel...

Laryngeal Papilloma is a respiratory disease that obstructs airflow from the body. Juvenile Laryngeal Papilloma is a rare condition causing overgrowths in the passage from the nose to the lungs. It majorly occurs in the vocal cords of children and...

Bartter's syndrome (BS) is a group of conditions involving enlargement of certain kidney cells, blood that is more alkaline than normal, high levels of potassium and chloride in the urine, loss of potassium from the kidneys (renal potassium wastin...

Kabuki syndrome is a rare, multisystem disorder characterized by multiple abnormalities including distinctive facial features, growth delays, varying degrees of intellectual disability, skeletal abnormalities, and short stature. A wide variety of ...

A keloid scar forms from abnormal healing, and usually develops in people 10 to 20 years old. A keloid, or keloid scar, is a kind of overgrown scar, or an overly aggressive healing response to a wound. It's a type of thick, irregul...

Kenny-Caffey syndrome type 2 (KCS2) is an extremely rare hereditary skeletal disorder characterized by thickening of the long bones, thin marrow cavities in the bones (medullary stenosis), and abnormalities affecting the head and eyes. Most cases ...

Keratitis ichthyosis deafness (KID) syndrome is a rare, genetic, multi-system disorder. It is characterized by defects of the surface of the corneas (keratitis), red, rough thickened plaques of skin (erythrokeratoderma) and sensorineural deafness ...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Keratosis follicularis, also known as Darier disease, is a rare, genetic skin disorder. Affected individuals develop skin lesions that consist of thickened, rough bumps (papules) or plaques that may also be greasy or have a brown or yellow crust. ...

Meleda disease is an extremely rare inherited skin disorder characterized by the slowly progressive development of dry, thick patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis). Affected skin may be unusu...

Haim-Munk syndrome is a rare genetic disorder characterized by the development of red, scaly thickened patches of skin on the palms of the hands and soles of the feet (palmoplantar hyperkeratosis), frequent pus-producing (pyogenic) skin infections...

Keratosis pilaris (KP) facts Keratosis pilaris is a very common, benign skin disorder that affects adolescents and adults. Keratosis pilaris causes numerous small, rough, tan or red little bumps around hair follicles on th...

Seborrheic Keratosis is a skin disorder usually characterized by discolored lesions that appear to be "stuck on" the skin surface. Warts may appear and skin is often oily or greasy. These skin lesions are sometimes mistaken for cancerous growths a...

Keratitis ichthyosis deafness (KID) syndrome is a rare, genetic, multi-system disorder. It is characterized by defects of the surface of the corneas (keratitis), red, rough thickened plaques of skin (erythrokeratoderma) and sensorineural deafness ...

Bilateral Renal Agenesis is the absence of both kidneys at birth. It is a genetic disorder characterized by a failure of the kidneys to develop in a fetus. This absence of kidneys causes a deficiency of amniotic fluid (Oligohydramnios) in a pregna...

The Course of Kidney Disease Diabetic kidney disease takes many years to develop. In some people, the filtering function of the kidneys is actually higher than normal in the first few years of their diabetes. Over several years, pe...

Kleine-Levin syndrome is a rare disorder characterized by the need for excessive amounts of sleep (hypersomnolence), (i.e., up to 20 hours a day); excessive food intake (compulsive hyperphagia); and behavioral changes such as an abnormally uninhib...

Knee bursitis facts A bursa is a fluid-filled sac that functions as a gliding surface to reduce friction between moving tissues of the body. There are three major bursae of the knee. Bursitis is usually not infec...

Kniest dysplasia is one of several forms of dwarfism that is caused by a change (mutation) in a gene known as COL2A1. This gene is involved in the production of a particular protein that forms type 2 collagen, which is essential for the normal dev...

Kohler disease is a rare bone disorder of the foot in children that may be the result of stress-related compression at a critical time during the period of growth. It is characterized by limping caused by pain and swelling in the foot. It most oft...

Kyphosis facts There are three main types of kyphosis: postural, Scheuermann's, and congenital. Most cases of kyphosis do not require any treatment. Physical therapy and exercise are often effective in postural a...

Laband syndrome, also known as Zimmerman-Laband syndrome, is an extremely rare genetic disorder characterized by abnormalities of the head and facial (craniofacial) area and the hands and feet. Most children with this disorder have abnormally larg...

Lamellar ichthyosis is a rare genetic skin disorder. In lamellar ichthyosis, the skin cells are produced at a normal rate, but they do not separate normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickl...

Lamellar ichthyosis is a rare genetic skin disorder. In lamellar ichthyosis, the skin cells are produced at a normal rate, but they do not separate normally at the surface of the outermost layer of skin (stratum corneum) and are not shed as quickl...

Laryngeal Papilloma is a rare medical condition in which non-cancerous tumors form along the aerodigestive tract. Laryngeal Papilloma grows inside the voice box, vocal cords, or the air passage from the nose to the lungs. The symptoms include brea...

Latex allergy facts Latex allergy is dramatically on the rise throughout the world. Latex allergy rises with exposure and is suspected to continue to rise until a latex substitute is found. Latex allergy can be s...

Legg-Calvé-Perthes Disease (LCPD) is one of a group of disorders known as the Osteochondroses. The Osteochondroses typically are characterized by degeneration (avascular necrosis) and subsequent regeneration of the growing end of a bone (ep...

Granuloma annulare is a chronic degenerative skin disorder. The most common form is localized granuloma annulare, which is characterized by the presence of small, firm red or yellow colored bumps (nodules or papules) that appear arranged in a ring...

Lichen planus facts Lichen planus is a chronic recurrent rash of unknown cause with no established cure. Lichen planus generally affects adults and can involve any portion of the body, but it has a predilection for the wri...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

No one knows the exact cause of psoriasis, but experts believe that it's a combination of things. Something wrong with the immune system causes inflammation, triggering new skin cells to form too quickly. Normally, skin cells are replaced every 28...

Lichen Planus is a rare, recurrent, itchy rash or area of inflammatory eruptions (lesions) of unknown origin characterized by shiny reddish-purple spots on the skin and gray-white ones in the mouth. The disorder may present as itchy spots on the w...

Lichen sclerosus facts Lichen sclerosus is a long-term problem of the skin that mostly affects the genital and perianal areas. Lichen sclerosus is most commonly seen in post-menopausal women. It is uncommon in men and chil...

Lichen sclerosus is a chronic skin disorder that most commonly affects post-menopausal women. However, it is sometimes identified among pre-menopausal women, and, even more rarely, among males. When found in males, the disease is known as balaniti...

Papular urticaria, usually called hives, is characterized by large numbers of very itchy red bumps (papules) that come and go every few days over a period of a month or so. The bumps are usually between 0.2 and 2 cm. in size and some may develop i...

Listeriosis is an infection caused by a gram-positive motile bacterium named Listeria monocytogenes. The infection produces fever, muscle aches, and, in many people, diarrhea. Severe infections can cause headaches, meningitis, convulsions, and dea...

Congenital lobar emphysema is a rare respiratory disorder in which air can enter the lungs but cannot escape, causing overinflation (hyperinflation) of the lobes of the lung. It is most often detected in newborns or young infants, but some cases d...

Osteogenesis Imperfecta (OI) is a group of rare disorders affecting the connective tissue and characterized by extremely fragile bones that break or fracture easily (brittle bones), often without apparent cause. The specific symptoms and physical ...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Urticaria pigmentosa is a rare skin disorder that is a localized (cutaneous) form of mastocytosis. Some clinicians suggest that urticaria pigmentosa is the childhood form of mastocytosis. Mast cells are specialized cells of connective tissue that ...

General DiscussionEndomyocardial fibrosis (EMF) is a progressive disease of unknown origin (idiopathic) that may seriously affect the heart. Its most obvious feature is a gross change in the makeup of the lining of the heart cavities (the...

Familial lipoprotein lipase (LPL) deficiency is a rare genetic metabolic disorder characterized by a deficiency of the enzyme lipoprotein lipase. Deficiency of this enzyme prevents affected individuals from properly digesting certain fats and resu...

Lumbar spinal stenosis facts Lumbar spinal stenosis is a condition whereby either the spinal canal (central stenosis) or one or more of the vertebral foramina (foraminal stenosis) becomes narrowed. Lumbar spinal stenosis i...

Jessner lymphocytic infiltrate of the skin is an uncommon disorder that is characterized by benign accumulations of lymph cells in the skin. These small lesions are solid, pink or red in color, and appear on the face, neck, and/or back. Skin surro...

Macular degeneration facts The macula is in the center of the retina, the light-sensitive layer of tissue at the back of the eye. The macula is responsible for central vision (straight-ahead vision). Degeneration of the macula occur...

What is male breast cancer? Men possess a small amount of nonfunctioning breast tissue (breast tissue that cannot produce milk) that is concentrated in the area directly behind the nipple on the chest wall. Like breast cancer in women, can...

What is male breast cancer? Men possess a small amount of nonfunctioning breast tissue (breast tissue that cannot produce milk) that is concentrated in the area directly behind the nipple on the chest wall. Like breast cancer in women, can...

Malignant carcinoid syndrome is characterized by a variety of signs and symptoms. Carcinoid tumors are neuroendocrine tumors that develop from primitive stem cells that can give rise to a variety of cell types. When a rare malignant...

Mesothelioma is a rare form of cancer that affects the membrane that covers and protects various internal organs of the body (mesothelium). The mesothelium is composed of two layers of specialized cells known as mesothelial cells. One layer direct...

Treacher Collins syndrome (TCS) is a rare genetic disorder characterized by distinctive abnormalities of the head and face area resulting from underdevelopment (hypoplasia) of certain facial structures including the jaw, cheekbones and nearby stru...

Marcus Gunn phenomenon is a rare genetic disorder that is usually present at birth. It is characterized by the movement of one upper eyelid in a rapid rising motion each time the jaw moves. Other eye abnormalities and vision difficulties may also ...

Marfan syndrome is a genetic disorder that affects connective tissue, which is the material between cells of the body that gives the tissues form and strength. Connective tissue is found all over the body and multiple organ systems may be affected...

Melasma facts Melasma is most common in women 20-50 years of age. Melasma looks like brown, tan, or blue-gray spots on the face (hyperpigmentation). Melasma is characterized by three location patterns (central fa...

Menopause is defined as the absence of menstrual periods for 12 months. It is the time in a woman's life when the function of the ovaries ceases. The process of menopause does not occur overnight, but rather is a gradual process. Th...

Menopause is defined as the absence of menstrual periods for 12 months. It is the time in a woman's life when the function of the ovaries ceases. The process of menopause does not occur overnight, but rather is a gradual process. Th...

Factitious disorders are conditions in which a person acts as if he or she has a physical or mental illness when he or she is not really sick. Factitious disorder by proxy is when a person acts as if a person in their care has an illness when they...

Microcephaly is a condition where the head (circumference) is smaller than normal. Microcephaly may be caused by genetic abnormalities or by drugs, alcohol, certain viruses, and toxins that are exposed to the fetus during pregnancy ...

Migraine is a type of headache that is usually characterized by a throbbing or pulsing pain on one side of the head, accompanied by nausea, vomiting, and sensitivity to light and sound. It is a neurological disorder that affects about 12% of the p...

Milk allergy is an abnormal response by the body's immune system to milk and products containing milk. It's one of the most common food allergies in children. Cow's milk is the usual cause of milk allergy, but milk from sheep, goats, buffalo and o...

Dextrocardia with Situs Inversus is a rare heart condition characterized by abnormal positioning of the heart. In this condition, the tip of the heart (apex) is positioned on the right side of the chest. Additionally, the position of the heart cha...

Megalocornea-mental retardation (MMR) syndrome, otherwise known as Neuhauser syndrome, is an extremely rare genetic disorder characterized by distinctive abnormalities of the eye, several degrees of cognitive impairment, and a wide variety of addi...

Moebius syndrome is a rare neurological disorder characterized by weakness or paralysis (palsy) of multiple cranial nerves, most often the 6th (abducens) and 7th (facial) nerves. Other cranial nerves are sometimes affected. The disorder is present...

Molluscum contagiosum facts A viral infection of the skin causes molluscum contagiosum, a mild skin disease. Risk factors include direct and indirect contact with an infected person's skin. Symptoms include painl...

Molluscum contagiosum is a common viral skin infection that causes small, raised bumps or lesions on the skin. It is caused by the molluscum contagiosum virus and is highly contagious, spreading through direct skin-to-skin contact or by sharing it...

Chromosome 9, Partial Monosomy 9p is a rare chromosomal disorder in which there is deletion (monosomy) of a portion of the 9th chromosome. Characteristic symptoms and findings include mental retardation; distinctive malformations of the skull and ...

Marinesco-Sjogren syndrome (MSS) is a rare genetic disorder that affects multiple organ systems of the body. Common symptoms include difficulty coordinating voluntary movements due to degeneration (atrophy) of the cerebellum (cerebellar ataxia), c...

Motor neuron disease comprises a group of severe disorders of the nervous system characterized by progressive degeneration of motor neurons (neurons are the basic nerve cells that combine to form nerves). Motor neurons control the behavior of musc...

The Mucopolysaccharidoses (MPS Disorders) are a group of rare genetic disorders caused by the deficiency of one of the lysosomal enzymes, resulting in an inability to metabolize complex carbohydrates (mucopolysaccharides) into simpler molecules. H...

Mucha-Habermann disease, also known as pityriasis lichenoides et varioliformis acuta or PLEVA, is a rare skin disorder. The lesions most often appear on the trunk and the arms and legs. Lesions tend to develop in small groups. Mucha-Habermann dise...

General DiscussionPseudo-Hurler polydystrophy (mucolipidosis type III) is a rare genetic metabolic disorder characterized by a defective enzyme known as UPD-N-acetylglucosamine-1-phosphotransferase. This defective enzyme ultimately result...

The Mucopolysaccharidoses (MPS Disorders) are a group of rare genetic disorders caused by the deficiency of one of the lysosomal enzymes, resulting in an inability to metabolize complex carbohydrates (mucopolysaccharides) into simpler molecules. H...

Mulibrey nanism is an extremely rare autosomal recessive genetic disorder characterized by profound growth delays and distinctive abnormalities of the muscles, liver, brain, and eyes. The acronym MULIBREY stands for (MU)scle, (LI)ver, (BR)ain, and...

Mayer-Rokitansky-Kuster-Hauser (MRKH) syndrome is a rare disorder that affects women. It is characterized by the failure of the uterus and the vagina to develop properly in women who have normal ovarian function and normal external genitalia. Wome...

Multiple epiphyseal dysplasia (MED) is a rare inherited spectrum of disorders characterized by malformation (dysplasia) of the "growing portion" or head of the long bones (epiphyses). Affected individuals may have an abnormally short thighbone (fe...

Hereditary multiple osteochondromas (HMO) is a rare genetic disorder characterized by multiple benign (noncancerous) bone tumors that are covered by cartilage (osteochondromas), often on the growing end (metaphysis) of the long bones of the legs, ...

Familial adenomatous polyposis (FAP) is a rare inherited cancer predisposition syndrome characterized by hundreds to thousands of precancerous colorectal polyps (adenomatous polyps). If left untreated, affected individuals inevitably develop cance...

Familial adenomatous polyposis (FAP) is a rare inherited cancer predisposition syndrome characterized by hundreds to thousands of precancerous colorectal polyps (adenomatous polyps). If left untreated, affected individuals inevitably develop cance...

Myofascial pain syndrome facts Muscle pain, tenderness, and spasm are characteristics of myofascial pain syndrome. Myofascial pain syndrome typically affects muscle in asymmetric areas of the body. The precise ca...

Nager Syndrome is a rare disorder that may or may not be genetically derived. Major symptoms may include underdevelopment of the cheek and jaw area of the face. Down-sloping of the opening of the eyes, a smaller than normal jaw, lack or absence of...

General DiscussionNeonatal lupus is a rare autoimmune disorder that is present at birth (congenital). Affected infants often develop a characteristic red rash or skin eruption. In addition, infants with neonatal lupus may develop liver di...

Nephrogenic diabetes insipidus (NDI) is a rare kidney disorder that may be inherited or acquired. NDI is not related to the more common diabetes mellitus (sugar diabetes), in which the body does not produce or properly use insulin. NDI is a distin...

Neuropathic pain is a pain condition that’s usually chronic. It’s usually caused by chronic, progressive nerve disease, and it can also occur as the result of injury or infection. If you have chronic neuropathic pain, it can fl...

Nocardiosis is an infectious pulmonary disease characterized by abscesses in the lungs. These abscesses may extend through the chest wall. The infection is spread through the body via the bloodstream by a microorganism called Nocardia asteroids....

Idiopathic nodular panniculitis is a rare spectrum of skin disorders characterized by single or multiple, tender or painful bumps below the surface of the skin (subcutaneous nodules) that usually lead to inflammation of the subcutaneous layer of f...

Diabetic Retinopathy is a complication of diabetes and a disorder of the light sensitive tissue of the eye (the retina). This condition is characterized by destructive changes in the blood vessels of the retina, which, if left unchecked, may lead ...

Epidermolysis bullosa (EB) is a genetic skin disorder characterized clinically by blister formation from mechanical trauma. There are four main types with additional sub-types identified. There is a spectrum of severity, and within each type, one ...

Renal glycosuria, also known as renal glucosuria, is a rare condition in which the simple sugar glucose is eliminated (excreted) in the urine despite normal or low blood glucose levels. With normal kidney (renal) function, glucose is excreted in t...

Nonketotic hyperglycinemia is an inborn error of metabolism characterized by the accumulation of large amounts of the amino acid glycine in blood, urine and, particularly, the cerebrospinal fluid (CSF). The metabolic block occurs in the conversion...

Norrie disease is a rare X-linked disorder that occurs due to errors or disruption (mutations) of the NDP gene. All males are affected by loss of vision present at birth or shortly thereafter. Additional symptoms may occur in some case...

Ocular rosacea is a type of rosacea that affects the eyes. It is characterized by redness, burning, stinging, and itching of the eyes, as well as dryness, sensitivity to light, and the formation of small cysts on the eyelids. In some cases, ocular...

Ollier disease is a rare skeletal disorder characterized by abnormal bone development (skeletal dysplasia). While this disorder may be present at birth (congenital); it may not become apparent until early childhood when symptoms, such as deformiti...

Onchocerciasis, also known as African River Blindness, is a parasitic infection caused by the filarial worm Onchocerca volvulus. It is transmitted to humans through the bite of an infected blackfly. Symptoms of the infection include severe itching...

Stickler syndrome refers to a group of disorders of connective tissue. Connective tissue, which is distributed throughout the body, multiple organ systems can be affected. The specific symptoms present in Stickler syndrome often vary greatly from ...

Neuromyelitis optica, also known as Devic disease (DD), is a chronic disorder of nerve tissue characterized by inflammation of the optic nerve (optic neuritis) and inflammation of the spinal cord (myelitis). There appear to be two forms of this di...

Osgood-Schlatter condition (formerly known as Osgood-Schlatter's disease) is a painful condition characterized by tiny, microfractures of the bony bump in the lower leg bone (tibia) where the ligament from the kneecap (patella) is inserted into th...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Erythrokeratolysis hiemalis is an extremely rare form of ichthyosis that was first described in South Africa but has subsequently been identified in other countries. In such cases, a link to South Africa has been determined. The disorder is charac...

Hyperoxaluria occurs when you have too much oxalate in your urine. Oxalate is a natural chemical in your body, and it's also found in certain types of food. But too much oxalate in your urine can cause serious problems. Hyperoxaluria can b...

Paget disease of the breast is a form of breast cancer that affects the skin of the nipple. The cause of Paget disease of the breast is poorly understood, but it may be related to tumor cells from other sites in the breast traveling...

Papillon-Lefevre Syndrome (PLS) is an extremely rare genetic disorder that typically becomes apparent from approximately one to five years of age. PLS is characterized by the development of dry scaly patches on the skin of the palms and the soles ...

Papillon-Lefevre Syndrome (PLS) is an extremely rare genetic disorder that typically becomes apparent from approximately one to five years of age. PLS is characterized by the development of dry scaly patches on the skin of the palms and the soles ...

Progressive supranuclear palsy, or PSP, is a rare neurodegenerative disease that is often misdiagnosed as Parkinson's disease because it carries similar symptoms. Because of its rarity, PSP is mostly unknown by the general public....

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

Penile cancer is a disease in which malignant (cancer) cells form in the tissues of the penis. The penis is a rod-shaped male reproductive organ that passes sperm and urine from the body. It contains two types of erectile tissue (spongy ti...

What is pericarditis? The heart muscle has a tight covering that surrounds it, a lining sac called the pericardium (peri=around +cardium=heart). This sac actually has two layers. The visceral pericardium is only one cell layer thick and fi...

Peritonitis is inflammation of the peritoneum — a silk-like membrane that lines your inner abdominal wall and covers the organs within your abdomen — that is usually due to a bacterial or fungal infection. Peritonitis can result from a...

Pertussis, also known as whooping cough, is a highly contagious respiratory infection caused by the bacterium Bordetella pertussis. It is characterized by severe coughing fits that can be followed by a "whooping" sound when the person tries to tak...

Phelan-McDermid syndrome is a rare chromosomal disorder in which a portion of the long arm (q) of chromosome 22 is missing (deleted or monosomic). Although the range and severity of symptoms may vary, Phelan-McDermid syndrome is generally thought ...

Phlebitis refers to inflammation of a vein and it can be caused by any insult to the blood vessel wall, impaired venous flow, or coagulation abnormality. Pain, swelling, redness, and tenderness are some common symptoms of phlebitis....

Phlebitis refers to inflammation of a vein and it can be caused by any insult to the blood vessel wall, impaired venous flow, or coagulation abnormality. Pain, swelling, redness, and tenderness are some common symptoms of phlebitis....

Familial hypophosphatemia is a rare inherited disorder characterized by impaired transport of phosphate and often altered vitamin-D metabolism in the kidneys. In addition, phosphate may not be well-absorbed in the intestines. The hypophosphatemia ...

Phosphoglycerate kinase deficiency is an extremely rare inherited metabolic disorder characterized by deficiency of the enzyme phosphoglycerate kinase. This enzyme is essential for the breakdown of glycogen, resulting in the release of energy. Sym...

Phosphoglycerate kinase deficiency is an extremely rare inherited metabolic disorder characterized by deficiency of the enzyme phosphoglycerate kinase. This enzyme is essential for the breakdown of glycogen, resulting in the release of energy. Sym...

Photokeratitis is a painful eye condition caused by exposure to ultraviolet (UV) radiation. It is sometimes referred to as "snow blindness" or "welder's flash." Symptoms of photokeratitis include redness, tearing, pain, and temporary vision loss. ...

Cholinergic urticaria is a relatively common disorder of the immune system characterized by an immediate skin reaction (hypersensitivity) to heat, emotional stress, and/or exercise. Symptoms of the disorder include the appearance of distinctive sm...

Cholinergic urticaria is a relatively common disorder of the immune system characterized by an immediate skin reaction (hypersensitivity) to heat, emotional stress, and/or exercise. Symptoms of the disorder include the appearance of distinctive sm...

Refsum disease is one of a family of genetic disorders known as the leukodystrophies in which, as a consequence of the disruption of lipid metabolism, the myelin sheath that insulates and protects the nerves of the brain fails to grow. It is inher...

Refsum disease is one of a family of genetic disorders known as the leukodystrophies in which, as a consequence of the disruption of lipid metabolism, the myelin sheath that insulates and protects the nerves of the brain fails to grow. It is inher...

Pierre Robin sequence is characterized by an unusually small lower jaw (micrognathia) and downward displacement of the tongue (glossoptosis). Some infants also have an abnormal opening in the roof of the mouth (cleft palate); both the soft and har...

Catel-Manzke syndrome is a rare genetic disorder characterized by distinctive abnormalities of the index fingers; the classic features of Pierre Robin syndrome; and, in some cases, additional physical findings. Pierre Robin syndrome refers to a se...

Catel-Manzke syndrome is a rare genetic disorder characterized by distinctive abnormalities of the index fingers; the classic features of Pierre Robin syndrome; and, in some cases, additional physical findings. Pierre Robin syndrome refers to a se...

Incontinentia Pigmenti (IP) is a rare genetic dermatological disorder affecting the skin, hair, teeth, and central nervous system. Progressive skin changes occur in four stages, the first of which appear in early infancy or can be present at birth...

Pinguecula and Pterygium are two common eye conditions that affect the conjunctiva, the thin, transparent membrane that covers the white part of the eye and the inner surface of the eyelids. A Pinguecula is a yellowish, slightly raised bump on the...

Pleurisy (pleuritis) is a health condition that occurs when the pleura, the thin layer of tissue that covers the lungs, becomes inflamed. Pleurisy (pleuritis) can be caused by a variety of things, including viruses, bacteria, and even lung cancer....

Pneumonia is an inflammatory infection that develops in the lungs. This disease fills up air sacs with fluid or pus that leads to cough with phlegm, fever, and difficulty in breathing. We inhale air from the nose or mouth that reach...

Pneumothorax (collapsed lung) is a medical condition in which either the lungs collapse on the whole or only a portion of the lungs collapse. In this condition, the air enters the area between the lungs and chest wall known as a plural stag. ...

Pneumothorax (collapsed lung) is a medical condition in which either the lungs collapse on the whole or only a portion of the lungs collapse. In this condition, the air enters the area between the lungs and chest wall known as a plural stag. ...

Polycystic ovary syndrome  Polycystic ovary syndrome is a disorder involving infrequent, irregular or prolonged menstrual periods, and often excess male hormone (androgen) levels. The ovaries develop numerous small collections of flui...

Polymyalgia rheumatica and giant cell arteritis facts Polymyalgia rheumatica causes pain and stiffness in muscles and joints. Polymyalgia rheumatica is diagnosed by characteristic symptoms associated with abnormal blood te...

Respiratory depression (hypoventilation) is a breathing disorder characterized by slow and ineffective breathing. During a normal breathing cycle, you inhale oxygen into your lungs. Your blood carries the oxygen around your body, deliverin...

Prader-Willi syndrome (PWS) is a genetic multisystem disorder characterized during infancy by lethargy, diminished muscle tone (hypotonia), feeding difficulties, and poor weight gain. In childhood, features of this disorder include short stature, ...

Preeclampsia is a pregnancy complication characterized by high blood pressure and signs of damage to another organ system, most often the liver and kidneys. Preeclampsia usually begins after 20 weeks of pregnancy in women whose blood pressure had ...

Primary central hypoventilation syndrome is a disorder affecting normal breathing.  It causes people to take shallow breaths resulting in a lack of oxygen and accumulation of carbon dioxide in the blood.  The com...

Psoriasis facts Psoriasis is a chronic inflammatory skin disease. Patients with psoriasis tend to be obese and are predisposed to diabetes and heart disease. Psoriasis can be initiated by certain environmental tr...

Pubic lice, also known as crabs, are tiny parasitic insects that infest the hair in the genital area. They are spread through close physical contact, such as sexual activity, and can cause itching and irritation in the affected area. Pubic lice ar...

Pulmonary alveolar proteinosis is a lung disorder characterized by a build-up of proteins, lipids, and other substances (together known as surfactants) in the lungs' air sacs, or alveoli. The alveoli are the air-holding cells in the lungs. The exc...

Damage and scarring in lung tissue lead to pulmonary fibrosis. The scars thicken the tissue around and between the air sacs in your lungs, making it difficult for oxygen to pass into the bloodstream.  The reason for scarring ca...

Pulmonary Infiltrates with Eosinophilia (PIE) is inflammation due to increased eosinophils, a type of white blood cell.  Pulmonary infiltrates with eosinophilia can be categorized into primary or idiopathic and secondary. ...

Lymphomatoid granulomatosis is a rare disorder characterized by overproduction (proliferation) of white blood cells called lymphocytes (lymphoproliferative disorder). The abnormal cells infiltrate and accumulate (form lesions or nodules) within ti...

Pump lung, (also known as Shock Lung), is inflammatory lung damage.  Pump lung is caused by fluid buildup in the lungs' small air sacs (called alveoli), which makes breathing very difficult. It also results in severely low bloo...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Infectious arthritis is an inflammation of one or more joints that occurs as a result of infection by bacteria, viruses or, less frequently, fungi or parasites. The symptoms of Infectious arthritis depend upon which agent has caused the infection ...

Acquired neuromyotonia is an inflammatory disorder characterized by abnormal nerve impulses from the peripheral nerves that result in continuous muscle fiber activity. Affected individuals often experience progressive muscle stiffness and cramping...

Reactive attachment disorder is a rare but serious condition in which an infant or young child doesn't establish healthy attachments with parents or caregivers. Reactive attachment disorder may develop if the child's basic needs for comfort, affec...

Recurrent Respiratory Papillomatosis (RRP) is the respiratory condition characterised by the presence of recurrent wart-like growths called papillomas around the vocal cords in the respiratory tract. It is caused by the Human Papill...

Respiratory Syncytial Virus (RSV) is a common respiratory virus that can cause mild, cold-like symptoms in adults and older children, but can be more serious in infants and young children. RSV is highly contagious and spreads through respiratory d...

Retinoblastoma is a rare form of eye cancer that affects the retina, the light-sensitive tissue at the back of the eye. It is most commonly found in children under the age of five, and is caused by a genetic mutation. Symptoms of retinoblastoma in...

Reye's syndrome is a rare and severe illness affecting children. Reye's syndrome is associated with viral infection and aspirin use. Patients with Reye's syndrome present with vomiting and mental-status changes. ...

Sydenham chorea is a rare neurological disorder characterized by rapid, involuntary, purposeless movements, especially of the face, feet and hands. Additional symptoms may include muscle weakness and emotional or behavioral problems. Sydenham chor...

Ringworm facts Ringworm is a common fungal infection of the skin and is not due to a worm. The medical term for ringworm is tinea. The condition is further named for the site of the body where the infection occurs. ...

Budd-Chiari syndrome is a rare disorder characterized by narrowing and obstruction (occlusion) of the veins of the liver (hepatic veins). Symptoms associated with Budd Chiari syndrome include pain in the upper right part of the abdomen, an abnorma...

General DiscussionRomano-Ward syndrome is an inherited heart (cardiac) disorder characterized by abnormalities affecting the electrical system of the heart. The severity of Romano-Ward syndrome varies greatly from case to case. Some indiv...

Parry-Romberg syndrome is a rare, acquired disorder characterized by slowly progressive shrinkage (atrophy) of the skin and soft tissues of half of the face (hemifacial atrophy). In rare cases, both sides of the face are affected. In some cases, a...

Rosacea (roe-ZAY-she-uh) is a common skin condition that causes redness and visible blood vessels in your face. It may also produce small, red, pus-filled bumps. These signs and symptoms may flare up for a period of weeks to months and then dimini...

Rosai-Dorfman disease is a rare disorder characterized by overproduction (proliferation) and accumulation of a specific type of white blood cell (histiocyte) in the lymph nodes of the body (lymphadenopathy), most often those of the neck (cervical ...

Rothmund-Thomson syndrome (RTS) is a rare genetic disorder that can affect many parts of the body. The disorder is characterized by distinctive abnormalities of the skin, sparse hair, eyelashes and/or eyebrows, small stature, skeletal and dental a...

Rubinstein-Taybi syndrome is a rare genetic multisystem disorder that affects many organ systems of the body. The group of findings (constellation) associated with this syndrome include growth retardation and delayed bone age; mental retardation; ...

Russell-Silver syndrome (RSS) is a rare disorder characterized by intrauterine growth retardation and postnatal growth deficiency along with a handful of common physical characteristics and a range of other symptoms. The wide spectrum of phenotype...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

The diencephalic syndrome is a very rare neurological disorder characterized by failure to thrive, abnormal thinness (emaciation), amnesia, intense sleepiness, unusual eye position and sometimes blindness. It is normally seen in infancy or early c...

Typhoid fever is a bacterial infection that is rare in the United States. However, it is not rare in many other countries. Major symptoms may include unusually high fever, headache, loss of appetite, fatigue, abdominal pain and diarrhea....

Scabies is an itchy, highly contagious skin disease caused by an infestation by the itch mite Sarcoptes scabiei. Direct skin-to-skin contact is the mode of transmission. A severe and relentless itch is the predominant symp...

Scabies is a highly contagious skin infestation caused by the microscopic mite Sarcoptes scabiei. It is characterized by intense itching and a pimple-like rash. Scabies is usually spread through close physical contact with an infected person, and ...

Toxic epidermal necrolysis (TEN) is a rare, sometimes life-threatening unless properly treated, immunological disorder of the skin. It is characterized by blisters that meld into one another to cover a substantial portion of the body (30% and more...

Psoriasis is an inflammatory disease of the skin that is estimated to affect about 2.2% of the adult population. Some people may have a genetic predisposition to psoriasis. The genes affected seem to be involved with control of the immune system. ...

A Schatzki ring is a narrowing of the lower esophagus that can cause dysphagia. Dysphagia means difficulty in swallowing. Dysphagia itself is rather common and occurs in about 3 percent of the population. The Schatzki ring is comprised of ...

Schizophrenia is a chronic, severe, debilitating mental illness that affects about 1% of the population, more than 2 million people in the United States alone. With the sudden onset of severe psychotic symptoms, the individual is sa...

Though they're not cancerous, sebaceous cysts can be irritating. A sebaceous cyst is a small lump or bump under the skin. This type of cyst is not cancerous. They are most often found on the face, neck, upper back, and upper chest,...

Seborrheic dermatitis facts Seborrheic dermatitis is probably the single most common inflammatory skin condition affecting humans aside from acne vulgaris. Seborrheic dermatitis is highly treatable but incurable. ...

Secondhand smoke is the combination of smoke from the burning end of a cigarette and the smoke exhaled by the smoker. It is dangerous to both smokers and nonsmokers. Secondhand smoke contains more than 7000 chemicals, including 70 that can cause c...

Shin splints facts Shin splints are a type of "overuse injury" to the legs. The pain is characteristic and located on the outer edge of the mid region of the leg next to the shinbone (tibia). It can be extreme and halt wor...

Shingles is a medical condition that is caused by the reactivation of the chickenpox-causing virus in the body. Shingles are extremely painful but it isn’t life-threatening.  Shingles is a painful rash that occurs anywher...

Shingles, also known as herpes zoster, is a viral infection caused by the varicella-zoster virus, the same virus that causes chickenpox. After a person has had chickenpox, the virus remains dormant in the nerve cells and can reactivate later in li...

Bloom syndrome is a rare genetic disorder characterized by short stature; increased sensitivity to light (photosensitivity); multiple small dilated blood vessels on the face (facial telangiectasia), often resembling a butterfly in shape; immune de...