In this week's issue of Nature, neuroscientists report that they've implicated a single gene mutation in Familiar Advanced Sleep Phase Syndrome (FASPS), or "early bird syndrome." Often, people who have this condition have no choice but to crash in the early evening and wake up long before dawn. From National Geographic News:
"The net result is you can feel very isolated," (FASPS sufferer Susan) Middlebrook said. "Who wants to party at three in the morning? Nobody I know, and I'm not headed to the local bar to see who's still there." Instead, she quietly cleans the house, makes breakfast, or cuddles up with a book.Link
About three-tenths of a percent of the world's population lives like this, including two of Middlebrook's sisters, her daughter, and her mother. "Their whole clock is shifted," said Ying-Hui Fu, a neuroscientist at the University of California, San Francisco...
The researchers are not yet certain how the gene mutation works to shift people's sleep time. But laboratory experiments suggest mutation slows the activity of a protein called casein kinase I delta (CKIdelta). "The next step is to figure out why," Fu said.