RLS, a common and debilitating sleep disorder, adversely affects the lives of tens of millions of people worldwide. The study findings were conducted by scientists at Emory University with colleagues at deCODE Genetics, Inc., an Icelandic genomics company, and Icelandic physicians at Landspitali in Reykjavik.

The findings will be presented June 12th at the 21st Annual Meeting of the Associated Professional Sleep Societies in Minneapolis, Minn.

RLS is a condition that produces an intense, often irresistible urge to move the legs because of creeping, crawling, tingling or burning sensations. RLS affects approximately 10 percent of the U.S. population, causing considerable discomfort, insomnia and sleep disruption in people of all ages. Symptoms can occur when people are awake or asleep.

David Rye, MD, PhD, professor of neurology at Emory University School of Medicine, director of the Emory Program in Sleep and lead author of the study, says the association between RLS and increased risk for high blood pressure was confirmed with the new study.

"Our results confirm and extend accumulating evidence that periodic leg movements of sleep (PLMs) seen in most RLS patients are associated with increased release of adrenaline," says Dr. Rye.

"Of greatest import, these findings suggest that the clinical significance of PLMs extends beyond sleep disruption and sleepiness," he says. "Our findings indicate that in addition to treating RLS symptoms, effective treatments may also need to target PLMs, particularly in patients at high-risk for cardiovascular disease (e.g., those with strong family histories of premature cardiovascular disease, smoking, etc.).

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In addition to identifying a fifth gene for JS, the study also sheds light on the role of cilia in this disease and possibly others. Primary cilia are tiny projections on cell surfaces that allow the inside of cells to communicate with their outside environment. Recent research has found that defects in cilia function lead to various newly identified syndromes called ciliopathies. The paper describes a genetic change that prevents interaction between two particular cilia proteins, presumably disrupting cilia function and causing JS. This links JS to other diseases such as Leber congenital amaurosis, Senior-Loken syndrome and nephronophthisis, the most common genetic cause of kidney failure in children. All these conditions share disruptions in the protein networks of cilia. Further, this study exemplifies the power of international collaborative research, an increasingly important trend in biomedical discoveries.

Study findings add substantially to the way JS and other ciliopathies will be identified and understood. By discovering this gene, we're on the forefront of research changing how we think about brain, retina and kidney development," said Dr. Dan Doherty, co-author on the study, from the Division of Genetics and Developmental Medicine at Seattle Children's Hospital Research Institute. These advances will lead to better understanding of both normal and abnormal brain development and eventually improved treatments for a variety of diseases."

Ongoing genetic research at Seattle Children's Hospital Research Institute will look for additional mutations responsible for Joubert syndrome, and continue to study how genes work together to build and maintain the brain, retina and kidney.

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