Scientists Discover Sleep-Kicking Gene

Late at night, Lynne Kaiser is awake.

It's a routine she has come to terms with over the last seven years, as her bout with restless legs syndrome (RLS) has become debilitating.

"It controls my life," she said.

Kaiser has had to go so far as to alter her occupation because RLS keeps her from holding a job during regular business hours.

"I created a job out of it. I'm an artist, so I did things I could do quietly late at night," she said. "I might go to bed from anywhere between 2 and 7 in the morning."

But by noon, her symptoms return, waking her and stealing much needed sleep for the rest of the day.

"I was not the mother I wanted to be because I didn't have the patience or the brain function or the ability to hold myself together," she said. "And God bless my husband -- I certainly wasn't the woman he married."

Kaiser's case is rare. Less than 3 percent of Americans are severely affected by RLS, and even fewer have the same troubles she does.

But what is normal about Kaiser's RLS experience is that, once she does fall asleep, she involuntarily kicks her legs.

"I own most of our bed. My husband gets about the top right eighth," she said. "Even the animals know: If they want to get into the bed, they don't lay near my legs at all."

Now, scientists may have pinpointed the gene that increases the chances that people will kick in their sleep. Their findings, which could have big implications for many RLS sufferers, are presented in the current issue of the New England Journal of Medicine.

"One of the components of RLS that is found in somewhere around 80 percent of patients was, in addition to having discomfort in the legs, that they move their legs in a dramatic fashion," said Dr. Kári Stefánsson, president of deCODE Genetics, a biotechnology company based in Reykjavik, Iceland.

The company, which has been tracking down disease genes since 1996, was heavily involved with the new study. This same company has successfully located other specific sections of DNA that contribute to diseases such as type 2 diabetes, heart attack and prostate cancer.

"The only thing that the variant does is to increase the probability of the disease," Stefánsson said, pointing out that having this form of the gene does not guarantee the leg-kicking symptom.

The study was initially done with 306 Icelanders who fit the criteria for RLS and who kicked their legs once they fell asleep -- an action known as periodic limb movements in sleep, or PLMs.

To check their work, the scientists repeated the study twice -- once again in Iceland, and another time in Atlanta -- finding the same gene variant each time.

"Once the Icelanders found it there, we wanted to make sure that we could generalize the finding," said Dr. David Rye, director of the Emory Healthcare Program in Sleep Medicine.

"Essentially we had 188 people from the Atlanta area, and we saw the exact same variant in the patients from here," he said. "It's not just chance or luck or a mistake."

Surprise Finding

Interestingly, the gene the researchers ended up discovering wasn't exactly what they set out to find. While they began in search of a gene specific to RLS, researchers instead found a link between DNA and kicking in sleep.

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