Background is inherited as an autosomal dominant disease that gives rise to progressive, elective (localized) neural cell death associated with choleric movements (uncontrollable movements of the arms, legs, and face) and dementia. It is one of the more common inherited brain disorders. About 25,000 Americans have it and another 60,000 or so will carry the defective gene and will develop the disorder as they age. Physical deterioration occurs over a period of 10 to 20 years, usually beginning in a person's 30's or 40's. The gene is dominant a ....