Legendary folksinger Woody Guthrie's fight with HD brought the disease into the public eye in the 1960s. Today, some 30,000 people in the United States are affected by the late-onset, autosomal dominant condition. Early symptoms--such as anger or depression, repetitive fidgety movements, and a clumsiness and tendency to fall--may go unnoticed for years. Neurological deterioration, reflecting cell death in the brain's striatum, typically continues for 15 to 20 years. HD has left its mark on the recent history of genetics, but has remained frustratingly untreatable. Discovery of a marker in 1983,4 and of the gene in 1993,5 gave affected families the option of predictive testing, but without any treatments that could halt or even slow the disease process.
As one of the first "triplet repeat" disorders to be described, HD is also one of eight "polygln" disorders in which an expanded repeat of the RNA triplet CAG adds extra glutamines ...
