Sleep duration: A review of genome-wide association studies (GWAS) in adults from 2007 to 2020.

A modest body of research exists in the area of human sleep genetics, which suggests that specific sleep phenotypes are, like many other complex traits, somewhat heritable. Until 2007 research into sleep genetics relied solely on twin studies, but in the last 13 years with the advent of huge biobanks and very large-scale genome-wide association studies, the field of molecular sleep genetics has seen important advances. To date, the majority have focused on self-reported sleep duration, but in recent years genome-wide association studies of objectively-measured sleep have emerged. These genetic studies have discovered multiple common genetic variants and as such, have provided insight into potential biological pathways, causal relationships between sleep duration and important disease outcomes using Mendelian randomisation. They have also shown that the heritability of these traits may not be as high as previously estimated. This article is the first to provide a detailed review of these recent advances in the genetic epidemiology of sleep duration. Studies were identified using both the GWAS Catalog and PubMed for completeness. Focus is on the genome-wide association studies published to date, including whether and how they have elucidated important biology and advanced knowledge in the area of sleep and health.