A degenerative brain disorder that usually appears in mid-life. Its symptoms, which include involuntary movement of the face and limbs, mood swings, and forgetfulness, get worse as the disease progresses. It is generally fatal within 20 years.

Dr. Danilo Tagle, of the National Human Genome Research Institute's Genetics and Molecular Biology Branch, defines Huntington's disease.

Related terms: animal model, dominant, gene, genetic code (ATGC),.