What is Huntington's disease?

Huntington's disease is a degenerative disease of the nervous system caused by a genetic mutation. Specifically, it results from the expansion of CAG repeats in the HTT gene, which leads to the production of an altered form of the huntingtin protein. This altered protein accumulates in neurons and causes progressive neurodegeneration, particularly affecting areas of the brain responsible for movement, emotion, and cognitive function.

The symptoms of Huntington's disease typically manifest in mid-adulthood and include motor dysfunction (such as chorea, which is characterized by involuntary movements), cognitive decline, and psychiatric problems. As the disease progresses, individuals experience increasing disability and a significant decline in quality of life. Understanding that this disease primarily impacts the nervous system helps contextualize its classification as a neurological disorder rather than other categories such as metabolic disorders, autoimmune disorders, or forms of cancer.