Overview of Huntington's Disease
Huntington's disease (HD) is a hereditary progressive neurodegenerative disorder characterized by the development of emotional, behavioral, and psychiatric abnormalities; loss of previously acquired intellectual or cognitive functioning; and movement abnormalities (motor disturbances). Also known as Huntington's chorea, the disorder is named for the American physician who initially described the condition in 1872.
The classic signs of HD include the development of choreaor involuntary, rapid, irregular, jerky movements that may affect the face, arms, legs, or trunkas well as the gradual loss of thought processing and acquired intellectual abilities (dementia). There may be impairment of memory, abstract thinking, and judgment; improper perceptions of time, place, or identity (disorientation); increased agitation; and personality changes (personality disintegration). Although symptoms typically become evident during the fourth or fifth decades of life, the age at onset is variable and ranges from early childhood to late adulthood (e.g., 70s or 80s).
HD is transmitted within families as an autosomal dominant trait. The disorder occurs as the result of abnormally long sequences or "repeats" of coded instructions within a gene on chromosome 4 (4p16.3). The progressive loss of nervous system function associated with HD results from loss of neurons in certain areas of the brain, including the basal ganglia and cerebral cortex.