Huntingtons Disease

Huntington’s Disease (HD) is an inherited neurological disorder which affects the central nervous system. HD is a dominant autosomal disorder, which means that only one gene copy from a parent is necessary for a person to have the condition. The disorder causes certain nerve cells in the brain to break down, which leads to a wide range of physical, cognitive and psychological symptoms. Symptoms usually start to appear in mid to late adulthood and worsen over a 10-20 year period. HD is a progressive disorder with no cure. The primary symptom associated with HD is involuntary movements and impaired muscle coordination, manifested in jerky, unlearned movements as well as muscle spasms. Additionally, people with HD often experience cognitive dysfunction, including memory loss, impaired decision-making skills, difficulty with planning and other executive functions, as well as depression and irritability. HD also causes physical changes within the brain, such as shrinkage in certain brain structures and clusters of abnormal proteins known as neuritic plaques. HD is caused by a single genetic mutation in one gene on chromosome 4. This mutation, known as CAG trinucleotide repeat expansion, results in an abnormally high number of “CAG” repeats, leading to an abnormal production of a protein known as huntingtin. This protein, in a abnormal form, accumulates in nerve cells of the brain and causes the nerve damage and other problems associated with the disorder. Person at risk for HD can be tested for the CAG trinucleotide repeat expansion, and those with the mutation can opt to undergo genetic counselling. With early detection, the progression of the disease can be slowed or halted with medication, nutrition and lifestyle changes. However, there is no cure for HD currently. HD is an inherited disease, and although it is relatively rare, it has a significant impact on those affected and their families. HD can be managed with medication and supportive services, and those affected by the disorder can still lead meaningful, independent lives.