Huntington's Disease

Overview, Causes, & Risk Factors

Huntington's disease is a progressive disorder involving wasting (degeneration) of nerve cells in the brain. The disorder was first described in 1872 by George Huntington, an American physician.

Huntington's disease is inherited as a single faulty gene on chromosome #4. There is a part of the gene that is repeated in multiple copies. The greater the number of repeats, the more likely it is that the person will develop symptoms and the greater the chance they will occur at a younger age. The disease may occur earlier and more severely in each succeeding affected generation because the number of repeats can increase.

Every child of a parent with the disorder has a 50% chance of inheriting Huntington's Disease. Symptoms do not usually appear until adulthood, typically between ages 35 and 50 years old but this depends on the number of repeats found in the gene so it may also appear in younger people. In children it may appear to be Parkinson's disease with rigidity, slow movements, and tremor.

There is progressive loss of mental function, including personality changes, and loss of cognitive functions such as judgment, and speech. Abnormal facial and body movements develop, including quick jerking movements. (The term chorea means "dance" and refers to the typical movements that develop.)