July 18, 2007 -- Two new studies identify the first gene variants associated with restless legs syndrome.
The studies appear in today's online editions of The New England Journal of Medicine and Nature Genetics.
Together, the studies pinpoint three common genetic variations that are linked to restless legs syndrome. The findings may lead to new treatments for restless legs syndrome, according to the researchers.
Other genes -- and environmental factors -- may also affect restless legs syndrome, in which people feel an irresistible urge to move their legs, particularly in the evening and at night.
Restless Legs Syndrome Genetics
The study published in The New England Journal of Medicine comes from doctors including Kari Stefansson, MD, PhD, of Decode Genetics in Reykjavik, Iceland, and David Rye, MD, PhD, an Emory University neurology professor.
They scanned the genes of 306 people in Iceland who have restless legs syndrome and more than 15,600 people in Iceland without restless legs syndrome.
The gene scans show that a certain variation in the BTBD9 gene was associated restless legs syndrome and other periodic limb movements during sleep.
The researchers confirmed that finding in follow-up gene studies in Iceland and the U.S.
The scientists don’t know exactly what the BTBD9 gene does. But their data suggest that eliminating that particular variation of the BTBD9 gene would wipe out half of the Icelandic and U.S. cases of restless legs syndrome that they studied.
"This is the most definitive link between genetics and RLS (restless legs syndrome) that has been reported to date," Rye says in an Emory University news release.
The study was partly funded by the Restless Legs Syndrome Foundation. Several of the researchers, including Rye and Stefansson, note ties to various drug companies or other financial interests in the topic.
The findings "offer hope to patients with periodic limb movements in sleep and RLS that the syndrome's pathophysiology [cause] will be understood and that such knowledge will lead to additional effective and durable treatments," writes editorialist John Winkelman, MD, PhD.
Winkelman works in the division of sleep medicine at Boston's Brigham and Women's Hospital and Harvard Medical School. His editorial appears in today's online edition of The New England Journal of Medicine.
More RLS Gene Clues
The BTBD9 gene also stood out in the restless legs syndrome gene study published in Nature Genetics.
So did two other gene variations -- one in the MEIS1 gene and the other in a chunk of DNA shared by the MAP2K5 and LBXCOR1 genes.
The researchers who pinpointed those genetic regions included Juliane Winkelmann, MD, of the Institute of Human Genetics in Munich, Germany. She's not related to editorialist John Winkelman.
The scientists screened the genes of more than 4,300 Germans and Canadians, including more than 1,500 people with restless legs syndrome.
The three gene variants identified in the study are common, but they may not be the only genes involved in restless legs syndrome, Winkelmann's team notes.
Winkelmann and five of her colleagues have filed a patent application connected to their research. They report no other competing financial interests.