21st June 2023

Pathophysiology

Huntington’s disease (HD) is an autosomal dominant neurodegenerative condition. It is caused by a CAG trinucleotide repeat mutation of the HTT gene, which encodes the protein huntingtin. Huntingtin is important in neuronal function. The CAG segment repeats an abnormal number of times – 36-120 times. It takes 40 CAG repeats for HD symptoms to develop. CAG repeats accumulate, causing symptoms to present earlier and more severely in subsequent generations, a phenomenon known as anticipation.