Huntington's disease is a completely penetrant autosomal dominant
neurodegenerative disease that is characterized by psychiatric disorders,
dementia and involuntary movements. The typical age of onset of HD os in the
fourth and fifth decades of life and the average duration of disease is
fifteen to twenty years. HD is currently incurable, and death results
usually from infectious complications of immobility. The social and
emotional impact of HD is disportionately greater than its prevalence
because its onset in the prime working years, the prolonged and progressive
course and the familial nature of the disease. Neuropathologic studies
indicate that neuronal loss is especially marked in the striatum with the
sparing of some subpopulations of striatal interneurons, and degeneration of
striatal projection neurons in a specific temporal sequence. A substantial
body of evidence suggests that neuronal death is due to an
N-methl-D-aspartate (NMDA) receptor-mediated excitotoxic mechanism.