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Study of Twins Reveals Gene Mutation Responsible for Short Sleep Duration

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Image credit: sterte via Flickr CC BY-NC-SA 2.0

According to the latest research published in recent edition of the journal of Sleep, the scientists, after the study on 100 pairs of twins, have found a gene mutation which could possibly offer a special advantage to its carrier: the expected ability to be engaged in normal function with sleep of less than six hours every night. Such genetic variant seems to allow resistance to the neurobehavioral effects of sleep deprivation as well.

Generally speaking, it is necessary to sleep seven to eight hours a night for most people. However the trend of insufficient sleep is now quickly turning into a public health epidemic. On the basis of the previous study targeted on a family of short sleepers who just needed six hours a night, it was uncovered that it was a mutation in the DEC2 gene — also known as BHLHE41 for basic helix-loophelix family member e41 that was the potential reason for such unusual power.

At present, a research team led by Renata Pellegrino from the Children’s Hospital of Philadelphia was trying to identify whether there still existed other variants of this gene.

In their research, scientists chose 100 twin pairs for sample tests. Of these twins 41 were dizygotic (fraternal twins) and 59 were monozygotic (identical twins). All twins came from the same sex and they were all healthy. By applying an actigraph unit to for measurement of sleep patterns, Renata Pellegrino’s team examined their nightly sleep duration at home for more than eight days. During its experiment, the team also measured the twins’ responses to 38 hours of sleep deprivation and the length of recovery sleep they needed.

As a result, one variant of the BHLHE41 gene, called Y362H, was discovered in one twin in a fraternal pair and such variant could ensure reduced sleep duration. It was also surprisingly found that even after sleep deprivation, compared with his twin, less recovery sleep was needed for him who demonstrated fewer performance lapses.

On average this participant only slept five hours every night, which was nearly one hour shorter than the non-carrier twin, who did sleep about six hours and five minutes each night. Besides that, the twin with the gene mutation had just 40 percent fewer lapses of cognitive performance on average for the period of the 38 hours of sleep deprivation; this measurement was made every two hours with the help of the Psychomotor Vigilance Test. This twin needed less recovery sleep afterwards as well. He just slept eight hours after the period of extended sleep deprivation, but his twin brother actually needed the sleep of 9.5 hours.

As Timothy Morgenthaler of the AmericanAcademy of Sleep Medicine said, the result of the new study showed that the need for sleep is a biological requirement rather than a personal preference.

It has to be further analyzed at the hypothesis that Benjamin Franklin, Margaret Thatcher, Winston Churchill and Napoleon did carry this gene variant.

Source: American Academy of Sleep Medicine

Journal reference: Pellegrino, R., et al. “A Novel BHLHE41 Variant is Associated with Short Sleep and Resistance to Sleep Deprivation in Humans.” Sleep 37.8 (2014): 1327.