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...

Apert syndrome, also known as acrocephalosyndactyly type I (ACS1), is a rare genetic disorder that is apparent at birth (congenital). The disorder is character-ized by distinctive malformations of the head that lead to distinctive facial features....

Blue rubber bleb nevus syndrome (BRBNS) is a rare blood vessel (vascular) disorder that affects the skin and internal organs of the body. Multiple distinctive skin lesions are usually characteristic of this disorder and are often present at birth ...

Turner syndrome is a rare chromosomal disorder that affects females. The disorder is characterized by partial or complete loss (monosomy) of one of the X chromosomes. Turner syndrome is highly variable and can differ dramatically from one person t...

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...

Camurati-Engelmann disease is a rare genetic disorder characterized by progressive widening and malformation of the shafts of the long bones (diaphyseal dysplasia). Major symptoms may include bone pain, particularly in the legs; skeletal abnormali...

Coffin-Lowry syndrome is a rare genetic disorder characterized by mental retardation; abnormalities of the head and facial (craniofacial) area; large, soft hands with short, thin (tapered) fingers; short stature; and/or various skeletal abnormalit...

Coffin-Lowry syndrome is a rare genetic disorder characterized by mental retardation; abnormalities of the head and facial (craniofacial) area; large, soft hands with short, thin (tapered) fingers; short stature; and/or various skeletal abnormalit...

General DiscussionCytochrome C Oxidase deficiency is a very rare inherited metabolic disorder characterized by deficiency of the enzyme cytochrome C oxidase (COX), or Complex IV, an essential enzyme that is active in the subcellular struc...

Cytomegalovirus infection (CMV) is a viral infection that rarely causes obvious illness. The virus that causes CMV is part of the herpes virus family and, like other herpes viruses, may become dormant for a period of time and then be reactivated. ...

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, ...

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...

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...

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...

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...

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, ...

Fibromyalgia facts Fibromyalgia is a pain syndrome characterized by chronic pain, fatigue, and tenderness to touch. Fibromyalgia is the most common cause of chronic, widespread pain in the United States. Fibromya...

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...

Pseudo-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 results in the accumulation of ce...

Gaucher disease is an inherited disorder of metabolism that interferes with many body functions. There are different forms of Gaucher disease. The perinatal lethal form is the most severe type of Gaucher disease. ...

Sprengel Deformity is a rare congenital disorder in which the shoulder blade is displaced upward. The elevated shoulder blade causes a lump in the back of the base of the neck and may limit movement of the arm on the affected side. This disorder t...

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...

Gaucher disease is a rare, inherited metabolic disorder in which deficiency of the enzyme glucocerebrosidase results in the accumulation of harmful quantities of certain fats (lipids), specifically the glycolipid glucocerebroside, throughout the b...

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, ...

Jansen 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 (bulbou...

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 ...

Klippel-Feil syndrome (KFS) is a rare skeletal disorder primarily characterized by abnormal union or fusion of two or more bones of the spinal column (vertebrae) within the neck (cervical vertebrae). Some affected individuals may also have an abno...

Alpha-mannosidosis is a rare genetic disorder characterized by a deficiency of the enzyme alpha-D-mannosidase. Alpha-mannosidosis is best thought of as a continuum of disease that is generally broken down into three forms: a mild, slowly progressi...

Alpha-mannosidosis is a rare genetic disorder characterized by a deficiency of the enzyme alpha-D-mannosidase. Alpha-mannosidosis is best thought of as a continuum of disease that is generally broken down into three forms: a mild, slowly progressi...

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...

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...

Turner syndrome is a rare chromosomal disorder that affects females. The disorder is characterized by partial or complete loss (monosomy) of one of the X chromosomes. Turner syndrome is highly variable and can differ dramatically from one person t...

Morquio syndrome (mucopolysaccharidosis type IV; MPS IV) is a mucopolysaccharide storage disease that exists in two forms (Morquio syndromes A and B) and occurs because of a deficiency of the enzymes N-acetyl-galactosamine-6-sulfatase and beta-gal...

I-cell disease (mucolipidosis II) is a rare inherited metabolic disorder characterized by coarse facial features, skeletal abnormalities and mental retardation. The symptoms of I-cell disease are similar to but more severe than those of Hurler syn...

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...

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, ...

Nail-patella syndrome (NPS) is a rare genetic disorder that is usually apparent at birth or during early childhood. Although the symptoms and physical characteristics associated with NPS may vary, characteristic abnormalities tend to include impro...

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 ...

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 ...

Turner syndrome is a rare chromosomal disorder that affects females. The disorder is characterized by partial or complete loss (monosomy) of one of the X chromosomes. Turner syndrome is highly variable and can differ dramatically from one person t...

Thrombocytopenia-absent radius (TAR) syndrome is a rare disorder that is present at birth (congenital). It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence (aplasia) of the long, thin bones of the forearms (r...

Camurati-Engelmann disease is a rare genetic disorder characterized by progressive widening and malformation of the shafts of the long bones (diaphyseal dysplasia). Major symptoms may include bone pain, particularly in the legs; skeletal abnormali...

Turner syndrome is a rare chromosomal disorder that affects females. The disorder is characterized by partial or complete loss (monosomy) of one of the X chromosomes. Turner syndrome is highly variable and can differ dramatically from one person t...

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...

Thrombocytopenia-absent radius (TAR) syndrome is a rare disorder that is present at birth (congenital). It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence (aplasia) of the long, thin bones of the forearms (r...

Three M syndrome is an extremely rare genetic disorder characterized by low birth weight, short stature (dwarfism), characteristic abnormalities of the head and facial (craniofacial) area, distinctive skeletal malformations, and/or other physical ...

Thrombocytopenia-absent radius (TAR) syndrome is a rare disorder that is present at birth (congenital). It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence (aplasia) of the long, thin bones of the forearms (r...

Thrombocytopenia-absent radius (TAR) syndrome is a rare disorder that is present at birth (congenital). It is characterized by low levels of platelets in the blood (thrombocytopenia) and absence (aplasia) of the long, thin bones of the forearms (r...

Tropical Sprue is a rare digestive disease in which the small intestine's ability to absorb nutrients is impaired (malabsorption). Consequently, nutritional deficiencies and abnormalities in the mucous lining of the small intestine may be present....

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 ...