Walsh & Hoyt: HUNTINGTON'S DISEASE

Huntington's disease is an autosomal-dominant disease of the CNS that becomes symptomatic in adulthood. It is characterized by an inexorably progressive movement disorder, usually chorea, and psychologic disturbances, including cognitive impairment and affective disturbances. These clinical features result from progressive degeneration of neurons within the basal ganglia and, to a lesser extent, elsewhere in the brain. In 1983, Gusella et al. discovered that the genetic mutation was localized to the short arm of chromosome 4 (195), but it was another 10 years before the genetic abnormality was identified as a variable increase in the number of CAG triplets in the huntingtin gene (Htt) (196).