Alpha-synuclein: One in a family of structurally related proteins that are prominently expressed in the central nervous system. Aggregated alpha-synuclein proteins form brain lesions that are hallmarks of some neurodegenerative diseases (synucleinopathies). The gene for alpha-synuclein, which is called SNCA, is on chromosome 4q21. Defects in this protein are believed to be related to the development of Parkinson disease.See also: Parkinson disease gene.
- Alport syndrome
Alport syndrome: A hereditary condition characterized by kidney disease, deafness, and sometimes eye defects. Alport syndrome involves inflammation of the kidney (nephritis), often progressing to kidney failure, and sensory nerve hearing loss. Progression to kidney failure is gradual and usually occurs in males before 50 years of age.
Alprazolam: A benzodiazepine sedative that causes dose-related depression of the central nervous system. Alprazolam is useful in treating anxiety, panic attacks, insomnia, and muscle spasms. The brand name is Xanax. A generic version is available.
ALPS: Autoimmune lymphoproliferative syndrome. ALPS is caused by genetic mutation most often in the FAS gene. It is characterized by non-malignant proliferations of lymphoid tissue resulting in enlargement of lymph nodes and liver and sometimes the spleen- which can result in hypersplenism- a condition in which a large spleen too actively filters the blood, lowering […]
- Aicardi syndrome
Aicardi syndrome: A genetic disorder characterized by the partial or complete agenesis of the corpus callosum (the structure that links the 2 hemispheres of the brain), infantile spasms (a characteristic form of childhood seizures), mental retardation, and an ocular (eye) abnormality called chorioretinal lacunae in which there are lacunae (holes) in the retina of the […]
AHD: Abbreviation for alveolar hydatid disease; American Hospital Directory; and atherosclerotic heart disease.