The term chorea comes from the Greek word choreia, which means "to dance." The term aptly describes the fitful, jerking movements associated with the condition. One form of chorea was first described by the English physician, Thomas Sydenham, in 1685, at which time the disorder was known as St. Vitus' Dance. This condition is now called Sydenham's chorea.
A second form of chorea has also been known for centuries, although it was first described in detail only in 1872 by the American physician, George Huntington (1850-1916). Huntington was born and lived in East Hampton, LongIsland, a community where chorea was widespread. His father and grandfather,also physicians, had both treated sufferers from chorea for many years. It was well known that the condition had been transmitted from Suffolk, England, to Connecticut in the seventeenth century by way of a single family, known asthe Bures family group. Members of the Bures family group had been frequentlyaccused of witchcraft and were among those convicted of this crime during the Salem witch trials.
Huntington, upon obtaining his medical degree from Columbia University, worked with his father in East Hampton, then moved to Palmyra, Ohio, before finally settling in Duchess County, New York. His paper on chorea was apparently his only published work, but was considered so exemplary that the disease he reported was eventually named for him.
Unlike Sydenham's chorea, which occurs most often in children and lasts onlya few weeks or months, Huntington's chorea does not strike until middle age and is always fatal. The disorder first appears as irregular and spasmodic movements of the muscles. Eventually these movements become so severe that a person is disabled. In his paper, Huntington wrote that in the final stages of the disease "the hapless sufferer is but a quivering wreck of his former self." Mental deterioration often accompanies these physical symptoms. The patientbecomes progressively worse until death occurs.
Huntington well described the terrifying outlook within families that had a history of chorea. Both the families and physicians knew that the disorder washereditary, but had no means of finding out who would be afflicted until late in life. Huntington reported that the outcome of the disease "is so well known to the sufferer and his friends, that medical advice is seldom sought."
The disorder became well known to the American public in the late 1950s and early 1960s when the popular folk singer, Woody Guthrie (1912-1967), developedthe condition. Guthrie's wife, Marjorie, and his son, Arlo Guthrie (b.1947),wrote and spoke about the agony they faced in dealing with Woody's illness as well as their uncertainties about Arlo's future as a father.
In 1993, after ten years of intensive research, scientists discovered the gene that causes Huntington's chorea. Even more important, four years later researchers uncovered how the mutated gene causes the devastating disorder. Investigators at the University of California at Los Angeles (UCLA) discovered that a genetic mutation results in the formation of 30 to 150 copies of glutamine (an amino acid) into certain proteins. As a result, the proteins clump together and then migrate into the nucleus of brain cells. This finding indicatesthat a single neurological mechanism may be responsible for inhibiting the production of neurotransmitters (substances that transmit nerve impulses) thatwould normally be produced by certain brain cells, resulting in the loss ofmuscular control characteristic of chorea. Scientists also know that the moreseverely the gene is mutated, the earlier the onset of the disease. Discovery of the genetic component and its functioning in Huntington's chorea has spurred research into drugs that would prevent the proteins from forming masses.Such drugs would, at the very least, delay the onset of symptoms.
The use of fetal cell transplants into the brain is regarded by some scientists as a promising treatment approach. In 1996, investigators at the Good Samaritan Hospital in Arizona announced the first successful use of fetal transplants to treat Huntington's chorea. Animal studies indicate that the transplanted cells are integrated into the brain's structure and then function normally to restore neural circuitry. In further patients studies, the scientists found some improvement in motor capacity and increased functioning lasting fromsix to nine months in some patients. However, outcomes have varied greatly among patients who have received transplants, and it is still not know whetherthe positive effects will persist over time. Other intriguing research currently under way includes using growth chemicals to stimulate brain stem cellsto produce new neurons and studies of brain implants using a cell that secretes a substance that may prevent nerve cell death.