Huntington disease

also called Huntington chorea a relatively rare, and invariably fatal, hereditary neurological disease that is characterized by irregular and involuntary movements of the muscles. Huntington disease is caused by a genetic mutation that causes degeneration of neurons in the basal ganglia, a pair of nerve clusters deep within the brain, that control movement. Symptoms usually appear between the ages of 35 and 50 and worsen over time. They begin with occasional jerking or writhing movements, called choreiform movements, or what appear to be minor problems with coordination; these movements, which are absent during sleep, worsen over the next few years and progress to random, uncontrollable, and often violent twitchings and jerks. Symptoms of mental deterioration may appear including apathy, fatigue, irritability, restlessness, or moodiness; these symptoms may progress to memory loss, dementia, bipolar disorder, or schizophrenia. The disease was first described by the American physician George Huntington in 1872.

A child of someone with Huntington disease has a 50 percent chance of developing the disease; a genetic test is available. No effective therapy or cure is available for the disorder, although choreiform movements may be partially and temporarily suppressed by phenothiazines or other antipsychotic medications.