For release: Friday, November 7, 1997Researchers from the National Institute of Neurological Disorders and Stroke have located a gene locus responsible for the most common human movement disorder, essential tremor (ET). In an article in the November 1997 issue of Movement Disorders,* Joseph J. Higgins, M.D., Lana T. Pho, and Linda E. Nee, M.S.W., report how they traced the gene to the short arm of chromosome 2.
"This is an important advance for a disorder that affects millions of Americans," says Zach W. Hall, Ph.D., Director of the National Institute of Neurological Disorders and Stroke. "It will lead the way to discovery of the gene, which should help us better understand the basis for this disabling condition."
ET is characterized mainly by tremor of the arms, but the head, neck and voice may also be involved. About 4 million Americans have this bothersome and sometimes disabling inherited disorder. ET affects approximately 1 to 6 percent of the adult population over the age of 40.
"The participation of an American family that has been disabled by tremor for five generations permitted us to employ a research technique called linkage analysis to locate the vicinity of an ET gene," says Dr. Higgins. "This finding lays the foundation for future research aimed at identifying the cause of ET. And it may eventually further our understanding of why people shake and benefit individuals with tremor through better diagnosis and treatment."
The discovery of a genetic susceptibility locus for ET is the first step toward finding the cause of the disabling neurologic condition. ET is commonly mistaken for Parkinson's disease, but is more common than Parkinson's. At the present time, there is no cure for ET and the only available treatments are medications such as the anti-seizure medication primidone and the beta-adrenergic blocking agent propranolol. Extreme cases of ET sometimes require surgery. These therapies offer only partial relief from the symptoms of ET and may have disturbing side effects. Many people prefer to live with the tremor rather than experience the discomfort of medication side effects.
"With President Clinton asking for more volunteerism in America, we can look with gratitude to the families who volunteer for neurogenetic studies," says Ms. Nee. "The progress in finding a marker for an ET gene is a tribute to these families. This discovery would not have been possible without the collaboration of concerned individuals who donated their time and blood for genetic studies."
The NINDS, one of the National Institutes of Health located in Bethesda, Maryland, is the nation's leading supporter of research on the brain and nervous system and a lead agency for the Congressionally designated Decade of the Brain.
*Higgins, Joseph J., Pho, Lana T., and Nee, Linda E. "A gene (ETM) for essential tremor maps to chromosome 2p22-p25." Movement Disorders, Vol. 12(6), 1997, pp. 859-864.
Originally prepared by Marcia Vital, NINDS Office of Communications and Public Liaison.
Last Modified August 7, 2009