Lights Out To Jet Lag?

A study of a Utah family of "morning lark" snoozers has led to discovery of the first human gene that controls the sleep cycle. The finding could lead to new treatments for jet lag, insomnia and other sleep problems.

Researchers, in a report published in Friday's edition of the Science journal, said they found the gene by studying the genetic pattern of four generations of a Utah family identified in 1999 as having a previously unknown condition called "familial advanced sleep-phase syndrome," or FASPS.

"This is a family of extreme morning lark sleepers," said Louis J. Ptacek, a Howard Hughes Medical Institute researcher at the University of Utah, Salt Lake City.

Ptacek said the family gets normal sleep, as deep and long as most people. The difference is that they start earlier and awaken earlier. Members of the family tend to grow sleepy in late afternoon and usually are slumbering in bed by 7 p.m. They generally awaken spontaneously around 2 a.m. For them, he said, it is a natural pattern.

The first FASPS family was identified in 1999 by Christopher Jones of the University of Utah. Since then, more than 20 others have been identified.

The new study, co-authored by Ptacek, Jones and others, used specimens from the family to find the genetic basis for the unusual sleep pattern.

Ptacek said the researchers found that FASPS is caused by a gene on chromosome 2 that changes a single amino acid among the 1,000 that make up a protein called hPer2. This change alters the action of an enzyme that has been linked in animal studies to control of the circadian rhythm, or sleep-wake cycle, he said.

Further study of this gene and the protein it makes might lead to drugs to control jet lag and other sleep disorders, Ptacek said.

"If we can understand how it works, we may be able to formulate a pill to match the FASPS mutation," he said. Such a pill, he said, could, theoretically, allow a jet traveler to advance the sleep cycle by about six hours, ideal for passengers flying from the United States to Europe.

"If we can learn how to advance the sleep clock, then we may also learn how to shift the clock back," which would benefit jet passengers flying west, said Ptacek.

Such drugs also would be useful for shift workers and others who must shift their sleep pattern abruptly, he said.

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