Sleepiness Might Be in the Genes, Study Finds

Oct. 26, 2010— -- No matter how little they sleep, some people can keep a skip in their step while others will yawn and struggle through the day. A new study from the University of Pennsylvania School of Medicine found that the reason could be in our genes.

Researchers found that healthy people with one particular genetic variant were generally sleepier than those without the gene. About 25 percent of the general public has the genetic variant, called DQB1 *0602, but only a small percentage of them actually suffer from sleep problems.

One person who has been told by his doctor that he may have this genetic variation is Robert Gibson, a 43-year-old machine shop supervisor in Milan, Illinois. Sleep is supposed to rejuvenate the body, but for Gibson, it can be anything but invigorating.

It would not be the only gene-linked sleep condition Gibson experiences; he already suffers from bouts of sleep paralysis, a disorder in which sufferers feel paralyzed as they fall asleep or as they wake up. Episodes can last a few seconds to a couple of minutes, but Gibson said the effects of the temporary paralysis seem to bog him down all day.

"It feels like I am drugged down, like there's a heavy weight on me the whole next day," said Gibson.

Gibson's sleep problems are more than just the garden-variety; years ago, doctor's did find a genetic biomarker that may have to do with his sleep disorders, and, because many genes probably contribute to sleep habits, doctors say Gibson probably has DQB1 *0602 as well.

"He hasn't been tested for this gene yet, but it could be part of the spectrum of genes that contribute to his sleep habits," said Dr. Mark Dyken, a professor of neurology at University of Iowa College of Medicine who treated Gibson.

For the study, researchers compared healthy people with the gene variant to healthy people without it to see if they suffered from any other sleep-related problems.

The research, published in the journal Neurology, found that people with the gene variant reported feeling sleepier and more fatigued compared to the people without the variant, whether they slept four hours or 10 hours. People with the gene variant also spent less time in deep sleep, and woke up more times during their sleep compared to the non-gene participants.

"When the genetic variant people were fully rested, they still rated themselves sleepy," said Dr. Namni Goel, lead author of the study and assistant professor of psychiatry at the University of Pennsylvania School of Medicine. "They had a lower drive to sleep when challenged by sleep loss, and overall they had a more fragmented sleep with more arousals in comparison to those who didn't carry the gene. We found it very interesting that they were healthy people, but when challenged, they looked like narcoleptics."