Astigmatism is a common eye condition that causes blurred vision due to an irregularly shaped cornea. It occurs when the cornea is curved more in one direction than the other, which causes light to be focused unevenly on the retina. This can cause...

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 ...

Batten disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic disorders known as the neuronal ceroid lipofuscinoses. These disorders share certain similar symptoms and are distinguished in part by the age a...

Batten disease, a rare genetic disorder, belongs to a group of progressive degenerative neurometabolic disorders known as the neuronal ceroid lipofuscinoses. These disorders share certain similar symptoms and are distinguished in part by the age a...

Bowen Hutterite syndrome is a rare genetic disorder that is apparent at birth (congenital). The disorder is characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failur...

Bowen Hutterite syndrome is a rare genetic disorder that is apparent at birth (congenital). The disorder is characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failur...

Maple syrup urine disease (MSUD) is a rare genetic disorder characterized by deficiency of certain enzymes (branched-chain alpha-keto acid dehydrogenase complex) required to breakdown (metabolize) specific amino acids in the body. Because these am...

Central serous chorioretinopathy (CSC) is a disorder of the eye in which fluid accumulates beneath the retina, causing it to detach from the back of the eye. This can lead to blurred vision, distortion of vision, and blind spots. CSC is usually ca...

Cerebral palsy facts Cerebral palsy (CP) is an abnormality of motor function, the ability to move and control movements. Cerebral palsy is acquired at an early age, usually less than a year of age. Cerebral palsy...

Chickenpox (varicella) is a viral infection that causes an itchy rash with small, fluid-filled blisters. Chickenpox is highly contagious to people who haven't had the disease or been vaccinated against it. Before routine chickenpox vaccination, vi...

Choroidal neovascular membranes (CNVM) are abnormal blood vessels that grow from the choroid, a layer of blood vessels that lies beneath the retina. These abnormal vessels can cause vision loss by leaking fluid and blood into the macula, the area ...

Collagenous colitis is a rare digestive disorder that primarily affects females and typically becomes apparent during middle age. The disorder is characterized by inflammatory changes of the mucous membranes (mucosa) of the colon (colitis) and abn...

  Cyclic vomiting syndrome is a disorder that causes recurrent episodes of nausea, vomiting, and tiredness (lethargy) most often in children but may occur in all age groups. Symptoms of cyclic vomiting syndrome are re...

Cysticercosis (pork tapeworm infection) facts Cysticercosis is a parasitic disease caused by ingesting the eggs of the pork tapeworm, Taenia solium. Humans are infected by ingesting raw or undercooked pork, and cysticercos...

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...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Dandy-Walker malformation (DWM) is a brain malformation that occurs during embryonic development of the cerebellum and 4th ventricle. The cerebellum is the area of the brain that helps coordinate movement, and is also involved with cognition and b...

Diabetes and foot problems facts Two main conditions, peripheral artery disease (PAD) and peripheral neuropathy, are responsible for the increased risk of foot problems in people with diabetes. People with diabetes have an...

Diabetic eye disease is a group of eye problems that can occur in people with diabetes. These eye problems can include diabetic retinopathy, cataracts, and glaucoma. Diabetic retinopathy is the most common form of diabetic eye disease and is cause...

Diabetic retinopathy is a complication of diabetes that affects the eyes. It occurs when high blood sugar levels damage the blood vessels in the retina, the light-sensitive tissue at the back of the eye. This can lead to vision loss or blindness. ...

Elbow pain facts The elbow joint is the area of union of three long bones. Tendinitis can affect the inner or outer elbow. Treatment of tendinitis includes ice, rest, and medication for inflammation. Ba...

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...

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...

The hereditary ataxias are a group of neurological disorders (ataxias) of varying degrees of rarity that are inherited, in contrast to a related group of neurological disorders that are acquired through accidents, injuries, or other external agent...

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...

Familial eosinophilic cellulitis is a rare skin disorder. It is characterized by raised, red, swollen, and warm areas of skin, in a flame-shaped pattern with associated pain. The exact cause of the disease is unknown. However, bites of spiders, be...

Gilbert syndrome is a mild genetic liver disorder in which the body cannot properly process bilirubin, a yellowish waste product that is formed when old or worn out red blood cells are broken down (hemolysis). Individuals with Gilbert syndrome hav...

Farsightedness, also known as hyperopia, is a vision condition in which distant objects appear clearly, but close objects appear blurry. It occurs when the eyeball is too short or the cornea has too little curvature, so light entering the eye is n...

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...

L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle s...

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...

Glutaricaciduria I (GA-I) is a rare hereditary metabolic disorder, caused by a deficiency of the enzyme glutaryl-CoA dehydrogenase. One of a group of disorders known as "organic acidemias," it is characterized by an enlarged head (macrocephaly), d...

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...

Granuloma annulare (gran-u-LOW-muh an-u-LAR-e) is a skin condition that most commonly consists of raised, reddish or skin-colored bumps (lesions) that form ring patterns — usually on your hands and feet. No one knows exactly what cau...

Familial eosinophilic cellulitis is a rare skin disorder. It is characterized by raised, red, swollen, and warm areas of skin, in a flame-shaped pattern with associated pain. The exact cause of the disease is unknown. However, bites of spiders, be...

Grover's disease is a rare, transient skin disorder that consists of small, firm, raised red lesions, most often on the skin of the chest and back. Diagnosis of this disorder becomes apparent under microscopic examination when the loss of the "cem...

Pallister-Hall syndrome (PHS) is an extremely rare genetic disorder that is typically apparent at birth. The symptoms and findings associated with the disorder may vary greatly in range and severity from patient to patient. However, in many indivi...

Walker-Warburg syndrome (WWS) is a rare multisystem disorder characterized by muscle, brain and eye abnormalities, often leading to death in the first weeks of life. However, the specific symptoms and severity of WWS can vary greatly from case to ...

Hemangioma is a benign (non-cancerous) tumor made up of a cluster of blood vessels. It is most commonly found in infants and young children, and usually appears as a red or purple mark on the skin. Hemangiomas can occur anywhere on the body, but a...

Histoplasmosis is a fungal infection caused by the fungus Histoplasma capsulatum. It is most commonly found in the soil of areas with high bird or bat droppings, such as caves, old buildings, and chicken coops. Symptoms of histoplasmosis can range...

HIV/AIDS and the Eye is a term used to describe the effects of HIV/AIDS on the eyes. HIV/AIDS can cause a variety of eye problems, including inflammation of the eye, dry eye, and vision loss. HIV/AIDS can also increase the risk of developing certa...

Holoprosencephaly (HPE) is the failure of the prosencephalon, or forebrain, to develop normally. The forebrain is a region of the brain in the fetus that develops into parts of the adult brain, including the cerebral cortex. Instead of the normal ...

Bowen Hutterite syndrome is a rare genetic disorder that is apparent at birth (congenital). The disorder is characterized by growth delays before birth (intrauterine growth retardation); failure to grow and gain weight at the expected rate (failur...

Carbamoyl phosphate synthetase I deficiency (CPSID) is a rare inherited disorder characterized by complete or partial lack of the carbamoyl phosphate synthetase (CPS) enzyme. This is one of five enzymes that play a role in the breakdown and remova...

Ornithine transcarbamylase (OTC) deficiency is a rare X-linked genetic disorder characterized by complete or partial lack of the enzyme ornithine transcarbamylase (OTC). OTC is one of six enzymes that play a role in the break down and removal of n...

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. ...

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...

Dercum's disease is an extremely rare disorder characterized by multiple, painful growths consisting of fatty tissue (lipomas). These growths mainly occur on the trunk, the upper arms and upper legs and are found just below the skin (subcutaneousl...

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...

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...

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 ...

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 ...

Lowe syndrome is characterized by vision problems including clouding of the lenses of the eyes (cataracts) that are present at birth, kidney problems that usually develop in the first year of life, and brain abnormalities that are associated with ...

Lowe syndrome is characterized by vision problems including clouding of the lenses of the eyes (cataracts) that are present at birth, kidney problems that usually develop in the first year of life, and brain abnormalities that are associated with ...

Lowe syndrome is characterized by vision problems including clouding of the lenses of the eyes (cataracts) that are present at birth, kidney problems that usually develop in the first year of life, and brain abnormalities that are associated with ...

Low back pain facts Functions of the low back, or lumbar area, include structural support, movement, and protection of certain body tissues. Pain in the low back can be a result of conditions affecting the bony lumbar spin...

Atypical mole syndrome, also called dysplastic nevus syndrome, is a disorder of the skin characterized by the presence of many mole-like tumors (nevi). Most people have 10-20 moles over their bodies. People with this syndrome often have more than ...

The methylmalonic acidemias are organic acidemias caused by an enzymatic defect in the metabolism of four amino acids (methionine, threonine, isoleucine and valine). This results in an abnormally high level of acid in the blood (academia) and body...

What is mitral valve prolapse? Mitral valve prolapse (also known as "click murmur syndrome" and "Barlow's syndrome") is the most common heart valve abnormality. The condition is slightly more prevalent in women than in men. The mitral valv...

Oculocerebrocutaneous (OCC) syndrome, a rare genetic disorder, is apparent at birth (congenital). The disorder is characterized primarily by eye (ocular), brain (e.g., cerebral), and skin (cutaneous) malformations. For example, many affected infan...

Oculocerebrocutaneous (OCC) syndrome, a rare genetic disorder, is apparent at birth (congenital). The disorder is characterized primarily by eye (ocular), brain (e.g., cerebral), and skin (cutaneous) malformations. For example, many affected infan...

Oral leukoplakia is a condition characterized by thick, white patches or plaques that form on the inside of the mouth, typically on the cheeks, gums, or tongue. These patches cannot be scraped off and may be rough or slightly raised. ...

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...

Pineal cysts are benign (non-cancerous) fluid-filled sacs located in the region of the brain that contains the pineal gland. Small pineal cysts (.5 cm or smaller) are common occurrences, often found incidentally on routine neurological exams. Smal...

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...

5-Oxoprolinuria is a biochemical finding that can arise from two underlying metabolic disorders. It is characterized by excretion of massive amounts of the chemical 5-oxoproline....

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. ...

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...

What is the rotator cuff? The rotator cuff is the group of four tendons that stabilize the shoulder joint. The tendons hook up to the four muscles that move the shoulder in various directions. There are four muscles whose tendons f...

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. ...

Sarcoidosis is a multisystem disorder that most often affects individuals between 20 and 40 years of age. Females appear to be affected more frequently than males. Sarcoidosis is characterized by the abnormal formation of inflammatory masses or no...

SHORT syndrome is a condition in which affected individuals have multiple birth defects in different organ systems. The term SHORT is an acronym with each letter representing one of the common findings in affected persons:(S)= short st...

General DiscussionSneddon syndrome is a rare progressive disorder affecting the blood vessels characterized by the association of a skin condition and neurological abnormalities. Characteristics include multiple episodes of reduced blood ...

Susac's syndrome is a rare disorder characterized by three main problems: impaired brain function (encephalopathy), partial or complete blockage (occlusion) of the arteries that supply blood to the retina (branch retinal artery occlusion, or BRAO)...

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...

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...

Congenital Varicella Syndrome is an extremely rare disorder in which affected infants have distinctive abnormalities at birth (congenital) due to the mother's infection with chickenpox (maternal varicella zoster) early during pregnancy (i.e., up t...

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...

Waardenburg syndrome is a genetic disorder that may be evident at birth (congenital). The range and severity of associated symptoms and findings may vary greatly from case to case. However, primary features often include distinctive facial abnorma...

L1 syndrome is an inherited, X-linked disorder occurring in males that primarily affects the nervous system. The disease is mainly characterized by hydrocephalus (increased fluid in the center of the brain), spasticity of the lower limbs (muscle s...