Huntington's disease

From Conservapedia

Huntington's disease is 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.

Sources

http://www.genome.gov/glossary.cfm?key=Huntington%27s%20disease