August 30, 1999--Researchers studying three families with the same unusual sleep pattern have uncovered the first hereditary sleep disorder in humans caused by a single gene. Neurologist Christopher Jones and Howard Hughes Medical Institute investigator Louis Ptácek, both at the University of Utah, are now searching for the gene that causes the disorder known as familial advanced sleep phase syndrome (FASPS).

Ptácek and his colleagues concluded that a single gene was responsible for FASPS by studying how the condition was passed along from one generation to the next within the affected families. In this case, inheritance seemed to follow the same simple pattern seen with other single gene traits, such as eye color.

"Our goal is to find the gene that is altered in FASPS and to use it to help us determine how the body's internal biological clock works," said Ptácek, whose research team published the findings in the September 1999 issue of the journal Nature Medicine. "Finding this gene might give us important leads not only for treating sleep disorders but also other problems related to human circadian rhythms."

All creatures -- from bacteria to humans -- seemingly operate on a biological clock synchronized to a 24-hour day. This internal clock controls a variety of daily biochemical and behavioral cycles -- including fluctuations in sleep and wakefulness -- that are collectively called circadian rhythms.

People with FASPS have a "fast" biological clock -- their internal clock's "day" is shorter than 24 hours. If left unconstrained by the demands of everyday life, people with a fast clock tend to go to sleep and wake up several hours earlier than normal. For example, the people examined in this study reported that while on vacation they tended to fall asleep earlier and wake up earlier than usual. In comparison, most people stay up la
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Contact: Jim Keeley
keeleyj@hhmi.org
301-215-8858
Howard Hughes Medical Institute
31-Aug-1999