AP-4-Associated Hereditary Spastic Paraplegia (AP-4-HSP) is a rare, inherited neurological disorder that affects the nerves in the lower body. It is characterized by progressive spasticity and weakness of the legs, leading to difficulty walking. I...

Attenuated familial adenomatous polyposis (AFAP) is a rare form of familial adenomatous polyposis (FAP) that is caused by a mutation in the APC gene. AFAP is characterized by the presence of fewer than 100 adenomatous polyps in the colon, which is...

APECED syndrome or Autoimmune polyendocrinopathy-candidiasis-ectodermal dystrophy syndrome is a genetic disorder. People...

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....

Apert Syndrome is a rare genetic disorder that affects the development of the skull, face, hands, and feet. It is caused by a mutation in the FGFR2 gene, which is responsible for the production of a protein that helps regulate the growth of bones ...

Aphakia is a condition in which the eye's natural lens is absent. It is usually caused by the surgical removal of the lens due to cataracts or other eye diseases. People with aphakia may experience blurred vision, difficulty focusing, and increase...

Aphalangy-hemivertebrae-urogenital-intestinal dysgenesis syndrome (AHUIDS) is a rare genetic disorder characterized by the absence of some or all of the fingers and toes (aphalangy), malformation of the vertebrae (hemivertebrae), malformation of t...

Aphalangy-syndactyly-microcephaly syndrome (ASM) is a rare genetic disorder characterized by the absence of some or all of the fingers and toes (aphalangy), webbing of the fingers and toes (syndactyly), and a small head size (microcephaly). It is ...

Aphasia, a disturbance in the formulation and comprehension of language, is due to damage to brain tissue areas responsible for language; aphasia may occur suddenly or develop over time, depending on the type and location of brain tissue damage....

Aphonia-deafness-retinal dystrophy-bifid halluces-intellectual disability syndrome is a rare genetic disorder that affects multiple systems of the body. It is characterized by aphonia (loss of voice), deafness, retinal dystrophy (degeneration of t...

Sutton disease II is characterized by the recurring eruption of painful inflamed ulcers in the mouth (stomatitis). There may be multiple ulcers of varying sizes. These ulcers in the mouth are commonly called canker sores. Sutton disease II is also...

Canker sores are small, painful ulcers on the inside of the mouth, lips, or throat. Symptoms of canker sores include small, painful, crater-like ulcers. See a doctor if canker sores are accompanied by fever, last more than...

Aplasia Cutis Congenita is a rare disorder with a complicated pattern of inheritance. Babies are born with the absence of certain layer(s) of skin, most often on the scalp, but also on the trunk, and/or arms and legs. The affected area is typicall...

Aplasia cutis congenita (ACC) is a rare congenital disorder characterized by the absence of skin at birth. It is usually seen as a localized defect on the scalp, but can also occur on other parts of the body. The cause of ACC is unknown, but it is...

Aplasia cutis congenita-intestinal lymphangiectasia syndrome is a rare genetic disorder characterized by the absence of skin (aplasia cutis congenita) at birth, intestinal lymphangiectasia, and a variety of other symptoms. Intestinal lymphangiecta...

Aplasia cutis-myopia syndrome is a rare genetic disorder characterized by the absence of skin (aplasia cutis) on the scalp and/or forehead, and myopia (nearsightedness). It is caused by a mutation in the PAX6 gene, which is responsible for the dev...