A team of researchers from Stanford University (USA) has identified a strong association between a sleep disorder known as narcolepsy and two genetic variants found in European individuals and those of Asian ancestry. As published today in the journal Nature Genetics , alterations in these genes produce a disorder of the immune system , and predispose our defense system to attack brain cells that produce hypocretin , a substance that regulates the sleep-wake cycle .
Narcolepsy is a disorder characterized by alteration of the REM phase of sleep, extreme daytime sleepiness, vision defects, and muscle weakness. It usually appears in adolescence and affects one in every 2,500 individuals in the US and Europe, but is four times more common among Japanese . Its genetic basis is also manifested in that the risk of suffering from it among first-degree relatives is between 10 and 40 times higher.
