Sparse whole genome sequencing identifies two loci for major depressive disorder

Major depressive disorder (MDD), one of the most frequently encountered forms of mental illness and a leading cause of disability worldwide(1), poses a major challenge to genetic analysis. To date no robustly replicated genetic loci have been identified (2), despite analysis of more than 9,000 cases(3). Using low coverage genome sequence of 5,303 Chinese women with recurrent MDD selected to reduce phenotypic heterogeneity, and 5,337 controls screened to exclude MDD, we identified and replicated two genome-wide significant loci contributing to risk of MDD on chromosome 10: one near the SIRT1 gene (P-value = 2.53×10(−10)) the other in an intron of the LHPP gene (P = 6.45×10(−12)). Analysis of 4,509 cases with a severe subtype of MDD, melancholia, yielded an increased genetic signal at the SIRT1 locus. We attribute our success to the recruitment of relatively homogeneous cases with severe illness.