A rare degenerative disease of the central nervous system, characterized by choreiform movements and mental deterioration.Huntington’s chorea was named after the American neurologist, George Huntington, who published a paper on it in 1872. The only psychiatric disorder known to follow a simple Mendelian ratio, this disease is carried by a dominant gene and affects 50 per cent of the children of a gene-carrying parent. In one study, over a thousand cases in the United States were traced to three individuals who came to this country in 1630. However, a few patients have recently been found with no family history of the disease. These cases were apparently due to a mutant gene.The disease occurs in both men and women between the ages of thirty and fifty. Its overt symptoms are often preceded for several years by a change in personality involving such symptoms as irritability, violence, vagrancy, depression and suicidal attempts. When the disorder becomes apparent, its most conspicuous physical symptoms are involuntary jerking and stretching (choreic) movements which usually begin in the facial muscles and gradually spread to the trunk and limbs. The movements subside during sleep, but are almost continuous during waking life. Most common are grimaces, smacking of lips, indistinct and explosive speech, and a shuffling gait. As these disturbances become more severe and uncontrollable, mental and emotional deterioration increase to a point where attention, memory, and judgment are seriously impaired, and hallucinations and paranoid delusions usually follow.Huntington’s chorea is a progressive disease which runs its course in ten to twenty years. There is no effective treatment, although drugs and surgery are frequently used to alleviate the involuntary movements. Its hereditary basis, however, offers hope for prevention through eugenics. But this hope is qualified by the fact that the disease does not manifest itself until after the normal age for having children. When the exact nature of the genetic effect is determined, it may be possible to develop a test which can be applied to all descendants of its victims