By Simon Makin
Around a third of people complain of some sleeplessness, and one in 10 meets diagnostic criteria for clinical insomnia. The costs, in terms of well-being, physical health and productivity, are enormous. From twin studies, researchers know the inability to fall or stay asleep has a genetic component, but the identities of the culprits were mostly unknown.
Now, two studies published Monday in Nature Genetics provide first peeks at the biological basis of insomnia, implicating specific brain regions and biological processes, and revealing links with heart disease and psychiatric disorders like depression. Both are genome-wide association studies (GWASs), which examine DNA from many thousands of individuals to determine where genetic markers related to health, disease or a particular trait reside.
The first study, from a team led by geneticist Danielle Posthuma of Vrije University Amsterdam, analyzed the genomes of over 1.3 million people, making it the largest GWAS of any complex trait to date. They used data from the UK Biobank, a large, long-term genetics project, and from the direct-to-consumer genetics company 23andMe to identify 202 areas of the genome linked to insomnia, implicating 956 genes, a big advance from the seven found previously. “I’m pretty confident the vast majority of these are real,” says geneticist Stephan Ripke, a GWAS expert at the Berlin Institute of Health who was not involved in either study. “But we need to confirm this in more, separate cohorts from different countries and researchers.”
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