Huntington's disease (HD) is a hereditary neurodegenerative disorder that causes involuntary movements, emotional disturbances and diminished cognitive abilities. The Huntington's Disease Society of America (HDSA) reports that over a quarter of a million Americans have HD or are at risk of inheriting it. HD leads to death approximately 10 to 20 years after its onset.

The name comes from Dr. George Huntington, the first person to describe the disorder in 1872.

HD is a genetic disease, passed from parent to child. The child of a parent with HD has a 50 percent possibility of inheriting the mutated HD gene. If the child does not receive the gene, he or she cannot develop or pass on the disease to their offspring. If the child does inherit the gene, development of HD is inevitable. Unlike many other diseases, HD affects all races and both sexes equally.

The NINDS reported that symptoms include depression, mood swings, driving difficulty, learning barriers, memory loss and indecisiveness. Intellectual tasks escalate in difficulty as the disease advances. Involuntary movements, referred to as Huntington's chorea, become more frequent as motor skills deteriorate.

Eventually, people with HD may have difficulty with simple tasks, such as feeding themselves and swallowing food. In time, people with HD become wholly dependent upon others for care.

HDSA reported that, in 1993, scientists have isolated the gene and developed a direct genetic test that can accurately determine if someone carries the gene.

"It can be done to confirm the diagnosis in someone who already has symptoms suggestive of HD," explained Ninith Kartha, a neurologist at Loyola University Medical Center, "or it can be done as a predictive test in someone who does not have symptoms, but is at risk for having the disorder due to his or her family history."

Many people who are at risk of contracting the disease opt to forgo the test since there is no cure for the disease. One must be at least 18 years of age to take a genetic test for HD unless she or he exhibits symptoms. If you get tested, HDSA recommended working with a testing center that provides pre- and post- test counseling.

There is no cure for HD, but there are drugs to relieve certain difficult symptoms. The only drug the U.S. Food and Drug Administration has approved to treat the involuntary writing and jerking movements is tetrabenazine (Xenazine). Side effects can include depression, fatigue, excitability and agitation.

The Mayo Clinic reported that antipsychotic drugs, such as haloperidol (Haldol) and clozapine (Clozaril) are also prescribed because they have the advantageous side effect of suppressing movements. Occupational therapy, psychotherapy, physical therapy and speech therapy may palliate various difficulties.

A large part of today's HD research focuses on testing therapies to delay the onset of symptoms or slow the progression of the disease. Kartha said, "Much of the work is still being done on animal models, but human trials with agents such as creatine and coenzyme Q10 are also being carried out."