Scientists have figured out why people with Huntington's disease suffer the destruction of only certain brain cells though an abnormal form of the huntingtin protein is present throughout the body. The culprit is a small protein named Rhes that is found almost exclusively in a movement-controlling brain region called the corpus striatum(線条体). When Rhes comes into contact with the mutated huntingtin protein, it sparks a toxic chemical reaction. There is no known cure for Huntington's disease, a rare hereditary disease of the nervous system characterized by involuntary(不随意の、無意識の)movements, emotional disturbances, and rapid mental degeneration progressing to dementia(痴呆).