Researchers discovered a genetic mutation that could explain why some individuals thrive on as little as three hours of sleep per night. The study, published on May 5 in the journal Proceedings of the National Academy of Sciences (PNAS), identifies the mutation SIK3-N783Y in the SIK3 gene, which plays a crucial role in regulating sleep and wakefulness.
This discovery adds to the growing body of research into natural short sleepers (NSS), people who comfortably function with less sleep than the average person without negative health consequences. Scientists have previously identified mutations in four genes—DEC2, NPSR1, GRM1, and ADRB1—associated with this rare trait.
In the recent study, researchers analyzed the DNA of volunteers who identified themselves as natural short sleepers. Among them was a healthy 70-year-old woman who reported needing only three hours of sleep per night. However, detailed actigraphy recordings revealed that she actually slept an average of 6.3 hours each night. Through whole-exome sequencing of her DNA, scientists discovered the SIK3-N783Y mutation.
To confirm the effects of the mutation, scientists conducted experiments on laboratory mice by introducing the genetic alteration. The genetically modified mice slept an average of 30 minutes less per night compared to normal mice. After periods of induced sleep deprivation, these mice slept up to 54 minutes less than their counterparts, confirming the mutation's impact on sleep duration.
The SIK3 gene produces a protein kinase, an enzyme that transfers phosphate molecules to other proteins, affecting their function. The N783Y mutation appears to cause structural changes in the SIK3 protein, impairing its ability to transfer these molecules. This alteration influences biochemical processes at the synapses—the connections between neurons—and affects sleep duration.
"These findings advance our understanding of the genetic underpinnings of sleep," the researchers stated. Understanding how the SIK3-N783Y mutation reduces the natural need for sleep may lead to new therapeutic strategies to enhance sleep efficiency and treat common sleep disorders like insomnia.
Natural short sleepers not only thrive on less sleep compared to others but also tend to feel worse if they sleep longer than usual. Despite getting only four to six hours of sleep, they do not suffer from daytime sleepiness or cognitive deficits, suggesting that specific genetic factors regulate their need for rest. The discovery of the SIK3-N783Y mutation sheds light on the genetic diversity that explains why the need for sleep varies among individuals.
"The body finishes processes like detoxification, cell repair, and brain cleaning in a shorter time, allowing them to function with less sleep than usual," explained Ying-Hui Fu, a researcher involved in the study. She added that these individuals "can perform at a higher level than we do all the functions that our body performs while we sleep."
Medical professionals typically recommend seven to nine hours of sleep each night for adults to function optimally. For most people, lack of sleep is associated with increased risks of chronic diseases, including diabetes, heart disease, and dementia. The SIK3-N783Y mutation could make some individuals more resistant to the negative effects of insufficient sleep.
The researchers hope that unraveling the genetic gift of natural short sleepers could help scientists find new drug targets for treating sleep disorders. By understanding how certain genetic mutations reduce the need for sleep without compromising health, new therapeutic approaches could be developed to improve sleep efficiency and mitigate the impacts of sleep deprivation.
While the SIK3-N783Y mutation is likely rare, its discovery is an important step in understanding how the brain regulates sleep. The study emphasizes that sleep, far from being a simple biological routine, is a complex function influenced by genetic factors that are still largely unknown.
The preparation of this article relied on a news-analysis system.
