Huntington's disease (HD) is a genetic disease which is transmitted as an autosomal dominant trait. It is a chronic degenerative disease of the CNS characterized by movement disorder, cognitive deterioration and personality change. While found in all parts of the world HD is most commonly found in Caucasians of whom about 1:10 000 individuals are affected. Onset is subtle and insidious and occurs most frequently between 30 and 50 years of age. Juvenile onset is seen in about 10% of cases and about 20% have onset at over 50 years of age with diagnoses as late as the eighth decade reported. The disease progresses inexorably, culminating in death usually 15 to 25 years after observed onset. Late onset HD tends to progress more slowly than early onset forms of the disease. There is thus far no effective treatment or cure for the disease.

HD is commonly known for its jerky, dance-like (choreic) movements. Movement may, however, also be rigid, especially in the juvenile form and the later stages of the adult form. Cognitive deficits (dementia) commonly associated with HD include difficulty with memory (primarily a retrieval problem), attention and concentration. While the dementia of HD is primarily subcortical and is non-aphasic, it includes many additional cognitive functions such as cognitive speed and fluency verbal fluency, difficulty persisting with, or initiating, a task and with change of set (see also ‘Dementias’).

Becoming affected with HD may have a tremendous impact on the psyche. Organic change is compounded with psychological trauma.