Huntington disease

Alternative names:

Huntington chorea

Definition:

An inherited disorder characterized by abnormal body movements and dementia.

Causes, incidence, and risk factors:

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

The disorder is inherited as a single faulty gene on chromosome #4. This is an autosomal dominant gene--if only one parent is affected, 50% of the children will be affected. The disease presents itself in many ways, however; some individuals being much less severely affected than others.

Symptoms do not usually appear until adulthood, typically between ages 35 and 50 years old. However, the disorder may appear in younger people. There is progressive loss of mental function, including personality changes, and loss of cognitive functions such as calculating, 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.)

Huntington disease affects about 5 out of 1,000,000 people.