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Can’t sleep? A new study has identified genetic causes of poor sleep

by TR Pakistan

Scientists have found 47 links between our genetic code and the quality, quantity and timing of how we sleep. The study include 10 new genetic links with sleep duration and 26 links with sleep quality. The paper titled “Genetic studies of accelerometer-based sleep measures yield new insights into human sleep behaviour” was published in the journal Nature Communications on April 5, 2019.  

The research looked at data from 85,670 participants of the UK Biobank and 5,819 individuals from three other studies, who wore accelerometers (wrist-worn devices similar to a Fitbit which record activity levels continuously.) The participants wore the accelerometers continuously for seven days, which allowed researchers to get more detailed sleep data. Previous studies have mostly relied on people accurately reporting their own sleep habits.

Among the genomic regions uncovered is a gene called PDE11A. The research team discovered that an uncommon variant of this gene affects not only how long you sleep but your quality of sleep too. The gene has previously been identified as a possible drug target for treatment of people with neuropsychiatric disorders associated with mood stability and social behaviours.

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The study also found that among people with the same hip circumference, a higher waist circumference resulted in less time sleeping, although the effect was very small — around four seconds less sleep per one cm waist increase in someone with an average hip circumference of around 100 cm.

Researchers found that collectively, the genetic regions linked to sleep quality are also linked to the production of serotonin, a neurotransmitter associated with feelings of happiness and wellbeing. Serotonin is known to play a key role in sleep cycles and is theorised to help promote deeper and more restful sleep.

“This study identifies genetic variants influencing sleep traits, and will provide new insights into the molecular role of sleep in humans. It is part of an emerging body of work which could one day inform the development of new treatments to improve our sleep and our overall health,” said lead author Dr Samuel Jones of the University of Exeter Medical School in a statement.

In addition, the researchers found further evidence that Restless Legs Syndrome, also called Willis-Ekbom Disease, is linked to poorer sleep from the genetic variants they found to be associated with sleep measures derived from the accelerometer data.

Dr Andrew Wood of the University of Exeter Medical School said, “We know that getting enough sleep improves our health and wellbeing, yet we still know relatively little about the mechanisms in our bodies that influence how we sleep. Changes in sleep quality, quantity and timing are strongly associated with several human diseases such as diabetes and obesity, and psychiatric disorders.” 

The international collaboration on the study was led by the University of Exeter and the team included researchers from the Center for Sleep and Circadian Neurobiology in Pennsylvania, Massachusetts General Hospital as well as the Netherlands, France and Switzerland. The research was funded by the UK Medical Research Council.