what gene is affected by huntington's disease
Huntington's disease (HD) is caused by a mutated form of the huntingtin gene, where excessive (more than 36) CAG repeats result in formation of an unstable protein. These expanded repeats lead to production of a huntingtin protein that contains an abnormally long polyglutamine tract at the N-terminus.
Disease-causing versions of the huntingtin gene contain more than 35 CAG repeats. In general, the greater the number of CAGs, the greater the chance that symptoms will appear earlier in life. Past studies have suggested that the onset of Huntingtonâs disease is also affected by other heritable factors. Researchers in the Genetic Modifiers of Huntingtonâs Disease Consortium postulated that studying people with expanded CAG repeats might help to pinpoint these other factors.