Huntington's disease

Huntington's disease, also called Huntington's chorea, causes intellectual impairment, emotional disturbances, and the uncontrollable arm, leg, and body movements that are its most characteristic feature. It is named for George Huntington, an American physician who first wrote about the disease in 1872. As a child, he had heard the condition described by his physician father and seen some patients affected by it. The incidence of Huntington's disease is estimated at between 4 and 10 out of every 100,000 births. About 25,000 Americans have been diagnosed with the disease, and over 100,000 are thought to have a family history that puts them at risk. Onset is usually between the ages of 35 and 45 but can occur in individuals younger than 20 and over 60. In the United States Huntington's disease became familiar to many people when popular folk singer Woody Guthrie became ill with the disease in the 1950s. Guthrie died in 1967 after being hospitalized for nearly 15 years.

Although the disease is known to be genetically transmitted, its exact cause is unknown. Physiologically, it is characterized by the death of brain cells (which cannot be replaced) and subsequent deterioration of the brain that follows a consistent pattern. The part of the brain that controls motor activity shrinks severely, the cells that carry nerve impulses to the brain are destroyed, and the balance of certain brain chemicals is disturbed. In autopsies, the brains of Huntington's patients have been found to weigh 150 to 500 grams less than normal brains. Genetically, Huntington's disease is an autosomal dominant disorder that can be passed on through either the mother or father. As a dominant genetic disorder, it cannot be passed on by individuals who don't have it themselves. The gender of the parent with Huntington's tends to affect the age of onset; persons with early onset usually inherit the disease from their fathers, those with later onsets from their mothers. A DNA marker for Huntington's disease was discovered by Dr. James Gusella in 1983, making it possible to test for the disease before the symptoms become apparent, although the tests require blood samples from at least two relatives of the person being tested. Prenatal testing has been available since 1986.

Unless there is a known familial history of the disease, Huntington's disease usually goes undiagnosed for years after its onset, as the lives of its victims and their families gradually deteriorate. The initial symptoms are often vague feelings of nervousness and restlessness. The victim's temperament undergoes a seemingly inexplicable change, as he or she becomes moody and irritable, and has periods of temper and depression that frighten and alienate family members. This behavior, together with the early signs of involuntary movement, is often mistaken for alcoholism, with the tragic result that people suffering from the disease are stigmatized by family and community just when they are most in need of help and emotional support. Because of the mental and emotional impairment associated with the disease, Huntington's victims become unable to function effectively at work, eventually losing their jobs or businesses. Many then drift from job to job. Even if alcoholism is not suspected, they may be shunned due to suspicions of insanity.

Between 5 and 10% of persons with Huntington's disease begin showing symptoms of the disease before the age of 20 (usually in adolescence). The symptoms tend to be more severe in children and adolescents than in adults, and the disease progresses more rapidly, often resulting in death within eight years. Epilepsy is especially common in young people with Huntington's and contributes to the frequent misdiagnosis of their condition, as does the onset of mental retardation. Another distinctive feature of the disease in children and adolescents is that the involuntary physical movements ("chorea") are often replaced by rigidity, either at the onset or later, thus resembling an unusual form the disease sometimes takes in adults, called the Westphal variant.

Although the number of children and adolescents who suffer from Huntington's disease is quite small, it strongly affects the lives of the far greater number of young people whose parents have been stricken with it and who may or may not go on to develop it themselves in later life. In addition to facing the knowledge that they may have Huntington's themselves (only a small percentage of family members take advantage of the available testing), these youths must cope with the disruption that any serious illness creates in a family. They may have the responsibility of caring for the ailing parent or contributing to the family income. Emotionally, they face the stigma associated with a disease that involves both physical handicaps and the appearance of insanity in the affected parent. A special problem associated with Huntington's is the danger that the parent's neurologically based emotional turbulence will lead to physical abuse, which it often does.

While there are no medications that can reverse or arrest the disease itself, drug therapy can help reduce the involuntary physical movements. Medication is sometimes prescribed for the mood disorders that accompany Huntington's disease, and counseling can often help relieve the chronic depression that is one of the hallmarks of the disease (it is estimated that as many as 25% of Huntington's patients commit suicide ). Regular exercise as well as physical, occupational, and recreational therapy can also help combat mental, emotional, and physical deterioration. Because Huntington's disease affects the mind, body, and emotions, a broad spectrum of professional help is needed to manage this illness, and a team approach has been recommended for this purpose. Huntington's patients can benefit not only from the services of physicians and nurses, but also from the work of physical, occupational, music, and speech therapists, as well as a variety of home health care personnel.

Further Reading

For Your Information

Books

• Folstein, Susan E. Huntington's Disease: A Disorder of Families. Baltimore: Johns Hopkins University Press, 1989.
• Phillips, Dennis H. Living with Huntington's Disease: A Book for Patients and Families. Madison: University of Wisconsin Press, 1981.

Gale Encyclopedia of Childhood & Adolescence. Gale Research, 1998.