Gene Cuts Need for Sleep

People With Rare Gene Mutation Refreshed by 6-Hour Sleep

From the WebMD Archives

Aug. 13, 2009 - At age 69 she's never slept more than six hours a day -- no naps -- yet she's healthy and far more active than most people.

Her 44-year-old daughter also goes to bed at 10 p.m. and gets up at about 4 a.m., even when on vacation. The two share a rare mutation in a gene called DEC2. People with this mutation, researchers find, need less sleep.

The gene is the first ever linked to human sleep behavior. The discovery comes from Ying-Hui Fu, PhD, of the University of California, San Francisco, and colleagues.

"The most interesting thing for me is this genetic mutation can lead to a human behavior trait," Fu tells WebMD. "We cannot blame everything on genetics, but it is obvious our genetic composition affects our behavior. What is involved in regulating our sleep need? This opens the door to start looking at this."

It's a key finding that other researchers have long been trying to find, says Mehdi Tafti, PhD, a geneticist and sleep researcher at the University of Lausanne, Switzerland. Tafti was not involved in the Fu study.

"This is the first time a gene has been found in humans that critically and dramatically controls sleep," Tafti tells WebMD. "We now have evidence that a gene mutation can dramatically change the amount of sleep you get."

Many people set their alarms to go off only six hours after they go to bed. But nearly all of them get some kind of "power nap" during the day to keep them going, says sleep expert Richard Simon Jr., MD, medical director of the Kathryn Severyns Dement Sleep Disorders Center in Walla Walla, Wash.

"Most people who get only six hours' sleep a night finally crash," Simon tells WebMD. "People who really need six hours' sleep and no more are in the minority. Most who get only six hours are going through life exhausted."

Short-Sleep Gene: First of Many to Come?

Although the discovery of the effects of the DEC2 mutation is a major finding, Tafti is quick to note that it affects only one part of the complex sleep process.