GWAS of 89,283 individuals identifies genetic variants associated with self-reporting of being a morning person

Circadian rhythms are a nearly universal feature of living organisms and affect almost every biological process. Our innate preference for mornings or evenings is determined by the phase of our circadian rhythms. We conduct a genome-wide association analysis of self-reported morningness, followed by analyses of biological pathways and related phenotypes. We identify 15 significantly associated loci, including seven near established circadian genes (rs12736689 near RGS16 , P =7.0 × 10 −18 ; rs9479402 near VIP , P =3.9 × 10 −11 ; rs55694368 near PER2 , P =2.6 × 10 −9 ; rs35833281 near HCRTR2 , P =3.7 × 10 −9 ; rs11545787 near RASD1 , P =1.4 × 10 −8 ; rs11121022 near PER3 , P =2.0 × 10 −8 ; rs9565309 near FBXL3 , P =3.5 × 10 −8 . Circadian and phototransduction pathways are enriched in our results. Morningness is associated with insomnia and other sleep phenotypes; and is associated with body mass index and depression but we did not find evidence for a causal relationship in our Mendelian randomization analysis. Our findings reinforce current understanding of circadian biology and will guide future studies. Circadian rhythms and related behaviours vary across individuals. Here, a large genome-wide association study reveals common single nucleotide variants influencing whether an individual reports as being a ‘morning person’ by identifying 15 significant loci, including 7 near known circadian genes.