A mega-analysis of genome-wide association studies for major depressive disorder.
Major Depressive Disorder Working Group of the Psychiatric GWAS Consortium None., Ripke S., Wray NR., Lewis CM., Hamilton SP., Weissman MM., Breen G., Byrne EM., Blackwood DHR., Boomsma DI., Cichon S., Heath AC., Holsboer F., Lucae S., Madden PAF., Martin NG., McGuffin P., Muglia P., Noethen MM., Penninx BP., Pergadia ML., Potash JB., Rietschel M., Lin D., Müller-Myhsok B., Shi J., Steinberg S., Grabe HJ., Lichtenstein P., Magnusson P., Perlis RH., Preisig M., Smoller JW., Stefansson K., Uher R., Kutalik Z., Tansey KE., Teumer A., Viktorin A., Barnes MR., Bettecken T., Binder EB., Breuer R., Castro VM., Churchill SE., Coryell WH., Craddock N., Craig IW., Czamara D., De Geus EJ., Degenhardt F., Farmer AE., Fava M., Frank J., Gainer VS., Gallagher PJ., Gordon SD., Goryachev S., Gross M., Guipponi M., Henders AK., Herms S., Hickie IB., Hoefels S., Hoogendijk W., Hottenga JJ., Iosifescu DV., Ising M., Jones I., Jones L., Jung-Ying T., Knowles JA., Kohane IS., Kohli MA., Korszun A., Landen M., Lawson WB., Lewis G., Macintyre D., Maier W., Mattheisen M., McGrath PJ., McIntosh A., McLean A., Middeldorp CM., Middleton L., Montgomery GM., Murphy SN., Nauck M., Nolen WA., Nyholt DR., O'Donovan M., Oskarsson H., Pedersen N., Scheftner WA., Schulz A., Schulze TG., Shyn SI., Sigurdsson E., Slager SL., Smit JH., Stefansson H., Steffens M., Thorgeirsson T., Tozzi F., Treutlein J., Uhr M., van den Oord EJCG., Van Grootheest G., Völzke H., Weilburg JB., Willemsen G., Zitman FG., Neale B., Daly M., Levinson DF., Sullivan PF.
Prior genome-wide association studies (GWAS) of major depressive disorder (MDD) have met with limited success. We sought to increase statistical power to detect disease loci by conducting a GWAS mega-analysis for MDD. In the MDD discovery phase, we analyzed more than 1.2 million autosomal and X chromosome single-nucleotide polymorphisms (SNPs) in 18 759 independent and unrelated subjects of recent European ancestry (9240 MDD cases and 9519 controls). In the MDD replication phase, we evaluated 554 SNPs in independent samples (6783 MDD cases and 50 695 controls). We also conducted a cross-disorder meta-analysis using 819 autosomal SNPs with P<0.0001 for either MDD or the Psychiatric GWAS Consortium bipolar disorder (BIP) mega-analysis (9238 MDD cases/8039 controls and 6998 BIP cases/7775 controls). No SNPs achieved genome-wide significance in the MDD discovery phase, the MDD replication phase or in pre-planned secondary analyses (by sex, recurrent MDD, recurrent early-onset MDD, age of onset, pre-pubertal onset MDD or typical-like MDD from a latent class analyses of the MDD criteria). In the MDD-bipolar cross-disorder analysis, 15 SNPs exceeded genome-wide significance (P<5 × 10(-8)), and all were in a 248 kb interval of high LD on 3p21.1 (chr3:52 425 083-53 822 102, minimum P=5.9 × 10(-9) at rs2535629). Although this is the largest genome-wide analysis of MDD yet conducted, its high prevalence means that the sample is still underpowered to detect genetic effects typical for complex traits. Therefore, we were unable to identify robust and replicable findings. We discuss what this means for genetic research for MDD. The 3p21.1 MDD-BIP finding should be interpreted with caution as the most significant SNP did not replicate in MDD samples, and genotyping in independent samples will be needed to resolve its status.