A process for repairing DNA breaks has been implicated as a possible explanation for the occurrence of a genetic error that causes over a dozen neuromuscular and neuro degenerative disorders, including Huntington’s disease, myotonic dystrophy and forms of spinocerebellar ataxia.
The error occurs as copies of three-letter sequences of DNA known as CAG and CTG triplets expand and repeat themselves hundreds or even thousands of times, disrupting normal gene sequences.