MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalitie...

MCT8-specific thyroid hormone cell transporter deficiency (THCT deficiency) is an inherited disorder that is characterized by severe mental retardation, an impaired ability to speak, diminished muscle tone (hypotonia), and/or movement abnormalitie...

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...

Giant axonal neuropathy is a rare neuropathy that severely affects the peripheral as well as the central nervous system. The first symptoms appear in early childhood. This disorder is characterized by abnormalities in the peripheral and central ne...

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 ...

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...

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...

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...

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...

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 ...

Mucolipidosis IV is a rare inherited metabolic disorder believed to be characterized by a deficiency of transport channel receptor protein, based upon the recent discovery of the Mucolipidosis IV gene. This deficiency may lead to the accumulation ...

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 ...

Biotinidase deficiency (BTD) is a treatable, metabolic disorder that is the result of a low concentration, or complete lack, of the enzyme, biotinidase. Biotinidase deficiency is an inherited disorder in which the body is not able to properly proc...

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...

Propionic Acidemia is a rare metabolic disorder characterized by deficiency of propionyl CoA carboxylase, an enzyme involved in the breakdown (catabolism) of the chemical "building blocks" (amino acids) of certain proteins. Symptoms most commonly ...

Very long-chain acyl-CoA dehydrogenase deficiency (VLCAD) is a rare genetic disorder of fatty acid metabolism that is transmitted as an autosomal recessive trait. It occurs when an enzyme needed to break down certain very long-chain fatty acids is...

Cri du chat syndrome (CdCS or 5p-) is a rare genetic disorder in which a variable portion of the short arm of chromosome 5 is missing or deleted (monosomic). Symptoms vary greatly from case to case depending upon the exact size and location of the...

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...

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...

Chromosome 18, Monosomy 18p is a rare chromosomal disorder in which all or part of the short arm (p) of chromosome 18 is deleted (monosomic). The disorder is typically characterized by short stature, variable degrees of mental retardation, speech ...

Wiedemann-Rautenstrauch syndrome (WRS), also known as neonatal progeroid syndrome, is a very rare genetic disorder characterized by an aged appearance at birth (old man look) growth delays before and after birth (prenatal and postnatal growth reta...

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

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

Short chain acyl-CoA dehydrogenase (SCAD) deficiency is a rare autosomal recessive genetic disorder of fatty acid catabolism belonging to a group of diseases known as fatty acid oxidation disorders (FOD). It occurs because of a deficiency of the s...

Succinic semialdehyde dehydrogenase (SSADH) deficiency is a rare inborn error of metabolism that is inherited as an autosomal recessive trait. In individuals with the disorder, deficient activity of the SSADH enzyme disrupts the metabolism of gamm...