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...

Agenesis of corpus callosum (ACC) is a rare disorder that is present at birth (congenital). It is characterized by a partial or complete absence (agenesis) of an area of the brain that connects the two cerebral hemispheres. This part of the brain ...

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...

Baller-Gerold Syndrome is a rare genetic disorder that is apparent at birth (congenital). The disorder is characterized by distinctive malformations of the skull and facial (craniofacial) area and bones of the forearms and hands. In in...

Fukuyama type congenital muscular dystrophy (FCMD) is one of several forms of a rare type of muscular dystrophy known as congenital muscular dystrophy. It is inherited as an autosomal recessive trait. Symptoms of this disorder are apparent at birt...

Branchio-oculo-facial syndrome (BOFS) is a very rare genetic disorder that is apparent at birth (congenital). As of 2004, only about 50 cases of BOFS had been reported in the medical literature. The symptoms of most BOFS patients include the proli...

Simpson dysmorphia syndrome types 1 and 2 are two forms of a rare, X-linked recessive, inherited disorder characterized by unusually large fetuses (prenatal overgrowth) and unusually large babies (postnatal overgrowth). In addition, affected indiv...

CHARGE syndrome is a rare disorder that arises during early fetal development and affects multiple organ systems. The term CHARGE comes from the first letter of some of the more common features seen in these children: (C) = coloboma (u...

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...

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...

Oculocerebral Syndrome with Hypopigmentation is an extremely rare inherited disorder characterized by the lack of normal color (hypopigmentation) of the skin and hair and abnormalities of the central nervous system that affect the eyes and certain...

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 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 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...

Cornelia de Lange syndrome (CdLS) is a rare genetic disorder that is apparent at birth (congenital). Associated symptoms and findings typically include delays in physical development before and after birth (prenatal and postnatal growth retardatio...

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), ...

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...

DOOR syndrome is a rare genetic disorder that may be recognized shortly after birth. "DOOR," an acronym for characteristic abnormalities associated with the syndrome, stands for (D)eafness due to a defect of the inner ear or auditory nerve (sensor...

Dubowitz syndrome is a very rare genetic and developmental disorder involving multiple congenital (inherited) anomalies including but not limited to: (1) growth failure/short stature; (2) unusual but characteristic facial features; (3) a small hea...

Chromosome 9, Trisomy 9p is a rare chromosomal syndrome in which a portion of the 9th chromosome appears three times (trisomy) rather than twice in cells of the body. The trisomy may involve a portion of the short arm (9p), the entire short arm, o...

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...

Tuberous sclerosis is a rare genetic multisystem disorder that is typically apparent shortly after birth. The disorder may be characterized by episodes of uncontrolled electrical activity in the brain (seizures); mental retardation; distinctive sk...

The hereditary sensory neuropathies (HSN) include 4-6 similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. The classification...

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...

A very rare syndrome characterized by abnormalities of the bones of the skeleton as well as mental retardation. Various facial, eye and urogenital anomalies are also present....

Fukuyama type congenital muscular dystrophy (FCMD) is one of several forms of a rare type of muscular dystrophy known as congenital muscular dystrophy. It is inherited as an autosomal recessive trait. Symptoms of this disorder are apparent at birt...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

Galloway-Mowat Syndrome, which is also known as Microcephaly-Hiatal Hernia-Nephrotic Syndrome, is an extremely rare genetic disorder that is characterized by a variety of physical and developmental abnormalities. Physical features may include an u...

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 ...

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...

Aniridia, cerebellar ataxia, and mental deficiency, also known as Gillespie syndrome, is an extremely rare inherited disorder that is characterized by the absence, in whole (aniridia) or in part (partial aniridia), of the colored portion (iris) of...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

Krabbe's Leukodystrophy is a rare inherited lipid storage disorder caused by a deficiency of the enzyme galactocerebrosidase (GALC), which is necessary for the breakdown (metabolism) of the sphingolipids galactosylceremide and psychosine. Failure ...

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...

Hartnup disease is a rare metabolic disorder inherited as an autosomal recessive trait. It involves an inborn error of amino acid metabolism as well as niacin deficiency. Factors that may precipitate acute attacks of this disorder may include poor...

The hereditary sensory neuropathies (HSN) include 4-6 similar but distinct inherited degenerative disorders of the nervous system (neurodegenerative) that frequently progress to loss of feeling, especially in the hands and feet. The classification...

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...

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 ...

Fetal retinoid syndrome is a characteristic pattern of mental and physical birth defects that results from maternal use of retinoids, the synthetic derivatives of vitamin A, during pregnancy. The most well known retinoid is isotretinoin (Accutane)...

Fetal retinoid syndrome is a characteristic pattern of mental and physical birth defects that results from maternal use of retinoids, the synthetic derivatives of vitamin A, during pregnancy. The most well-known retinoid is isotretinoin (Accutane)...

Juberg-Marsidi syndrome is an extremely rare X-linked genetic disorder that is fully expressed in males only, and is apparent at birth (congenital) or during the first few weeks of life (neonatal period). Affected children exhibit severe mental re...

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 ...

Chromosome 3, Monosomy 3p is a rare chromosomal disorder in which the end (distal) portion of the short arm (p) of chromosome 3 is missing (deleted or monosomic). The range and severity of symptoms and findings may be variable. However, associated...

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 ...

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...

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 ...

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...

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 ...

Branchio-oculo-facial syndrome (BOFS) is a very rare genetic disorder that is apparent at birth (congenital). As of 2004, only about 50 cases of BOFS had been reported in the medical literature. The symptoms of most BOFS patients include the proli...

Chromosome 21 Ring is a rare chromosomal disorder in which the affected infant has a breakage of chromosome 21 at both ends, and the ends of the chromosome join together to form a ring. The amount of genetic material lost at the two ends of the ch...

Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate mental retardation and multiple birth defects including particular facial fea...

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; ...

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; ...

Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate mental retardation and multiple birth defects including particular facial fea...

Smith-Lemli-Opitz syndrome (SLOS) is a variable genetic disorder that is characterized by slow growth before and after birth, small head (microcephaly), mild to moderate mental retardation and multiple birth defects including particular facial fea...

Smith-Magenis syndrome is characterized by particular facial features, developmental delays, mental retardation and behavioral abnormalities. The facial features include a broad square-shaped face, an abnormally short, broad head (brac...

Smith-Magenis syndrome is characterized by particular facial features, developmental delays, mental retardation and behavioral abnormalities. The facial features include a broad square-shaped face, an abnormally short, broad head (brac...

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

Filippi syndrome is an extremely rare genetic disorder that may be apparent at birth (congenital). The disorder is characterized by an unusual facial appearance, abnormalities of the fingers and toes, and mild to severe mental retardation. Primary...

Wieacker syndrome is a rare, slowly progressive, genetic disorder characterized by deformities of the joints of the feet (contracture), muscle degeneration (atrophy), mild mental retardation and an impaired ability to move certain muscles of the e...

Wieacker syndrome is a rare, slowly progressive, genetic disorder characterized by deformities of the joints of the feet (contracture), muscle degeneration (atrophy), mild mental retardation and an impaired ability to move certain muscles of the e...

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...

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), ...