Japanese scientists have identified a gene variant that may be linked to narcolepsy, a condition marked by excessive daytime sleepiness, impaired vision and muscle weakness. It occurs in 1 out of 2,500 individuals in the United States and Europe, but is at least 4 times more frequent in Japanese.The researchers analyzed the genomes, or DNA, of more than 200 narcoleptic Japanese and almost 400 others who did not have that condition, and one gene variant occurred with significant frequency among those with narcolepsy. Identification of this gene variant could pave the way for experts to hunt for a treatment.
The gene is located between the genes CPT1B and CHKB, both of which appear to be linked to the disorder. CPT1B controls an enzyme that regulates sleep, while CHKB is linked to the sleep-wake cycle. The scientists took a further step to examine that same gene variant in more than 400 Koreans, 800 European and 200 African Americans. It occurred with significant frequency among narcoleptic Koreans, but the association was not evident in the Europeans and African Americans.
As medical disorders go, narcolepsy has the paradox of being popularly portrayed in comedy, but being a rare, devastating and poorly understood condition in real life. Only one in 2,000 people have the disease, which means doctors can rarely get enough patients or funding to really study narcolepsy and make advances to treat it. But Nature Genetics researchers reported that they discovered a genetic variant which increases a person's susceptibility to narcolepsy by 79 percent.
