To prioritize genes that may play a functional role in BD, we integrated BD GWAS association statistics with eQTL (SNP-gene expression association) and mQTL (SNP-DNA methylation association) data using summary Mendelian randomization (SMR) 48,49,50 (Supplementary Table 16; Supplementary Note). SMR identified 21 genes using eQTL data that were significant after multiple testing correction, without evidence of heterogeneity between GWAS and eQTL association signals. Association with GNL3 was observed in both brain and blood, highlighting the utility of using blood eQTL data as proxy for brain eQTLs 50. Methylation profiles at 6 CpGs in brain and 10 CpGs in blood were associated with BD, four of which overlapped between brain and blood mQTL: MUSTN1, GLT8D1, HAPLN4 and FADS2.
