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Hope on the Horizon for Common Genetic Sleep Disorder Restless Legs: Presented at SFN

By Glynn Wilson

NEW ORLEANS, LA -- November 13, 2003 -- There may be hope on the horizon for people with the common genetic sleep disorder, restless legs syndrome, according to a study presented here November 12^th at the Annual Meeting of the Society for Neuroscience.

"This is evidence for a familial clustering and possibly for a genetic basis," said presenter Dr. Wayne A Hening, MD, PhD, Johns Hopkins Bayview Medical Center, Baltimore, Maryland.

"This [familial clustering] has been found before, but never in which the relative diagnosis was done blinded," he said. Dr. Hening and his team found that the relatives of patients with restless legs and the patients themselves started to develop the symptoms at about the same age. In the relatives, the syndrome lasted an average of 18 years, he said.

Restless legs syndrome (RLS) is a common sensorimotor disorder that involves uncomfortable sensations coupled with an urge to move, Dr. Hening said. It tends to come on later in the day when people are trying to relax or go to sleep. "It can be quite distressing and disruptive of sleep," he said.

In this study, 484 individuals in the families of 55 RLS probands and 32 control probands were diagnosed by Dr. Hening, who was blinded to the identity of their families or the proband diagnosis. The diagnosis was then reviewed by at least one additional expert, who determined symptom character, measures of severity, age of onset and persistence of the disorder.

Family members were divided into three groups. First and second-degree relatives of RLS probands and first-degree relatives of control probands, compared the relatives with definite diagnoses of primary RLS (n = 66, n = 37, n = 10, respectively) to the RLS probands (n = 52).

Eleven percent of the probands described symptoms as being painful compared to 25%, 19%, and 30% of relatives, respectively. In addition, 92% of probands had daily symptoms compared to 11%, 19%, and 20% of relatives; 52%, 35%, and 60% of relatives had symptoms less than once a week; 42% of probands, but no relatives, had symptoms that began before 6 p.m.

Mean age of symptom onset (standard deviation) was 34.7 years (17.1 years) for probands compared to 26.8 years (15.3 years), 36.5 years (17.2 years) and 26.7 years (11.1 years) in relatives. All probands had current symptoms as well as 99% of relatives.

The researchers concluded that family members diagnosed with restless leg syndrome had similar quality of symptoms, age at onset, and persistence of symptoms as did patients, but had a lower frequency of symptoms, and their symptoms began later in the day.

The two major messages for the family doctor, he said, are that it is a very common condition and if you understand the most common features, you can recognize it fairly easily.

There are no approved medications for treatment of restless leg syndrome in the United States, Dr. Hening said. "But there's a lot of interest in the industry," he said. "It is to be expected that within the next year or two one or more will appear on the market."


[Study title: A Comparison of the Restless Legs Syndrome in Patient Probands and Definitely Affected Family Members. Abstract 769.1]

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