The Enigma of Huntington's Disease; December 2002; Scientific American Magazine; by Elena Cattaneo, Dorotea Rigamonti and Chiara Zuccato; 6 Page(s)

Unusual grimaces are normally the first sign that something is wrong. Next, affected people become more and more absentminded and begin to display involuntary gestures, especially when under psychological or physical stress. As the disease progresses, the dancelike movements-which may be confused with drunkenness-occur more frequently and become disabling. People lose their capacity to perform simple, everyday tasks and show impairments in intellectual abilities such as planning. In the later stages, depression and aggressiveness-and, in the most severe cases, dementia and psychosis-take over, reducing a formerly healthy, vital family member, friend or co-worker to a miserable, bedridden shadow.

This is the grim picture of Huntington's disease, a heritable disorder that commonly strikes people who have the predisposing gene during the prime of life, the 30s or 40s. No effective treatment exists, so the disease advances slowly but inexorably, generally leading to total disability and death after 15 or 20 years. Although Huntington's primarily affects the central nervous system, most individuals suffering from it eventually die from heart or respiratory complications, as a result of their being confined to bed, or from having sustained head injuries caused by frequent falls.