in the major histocompatibility complex (MHC) while the others are in or near the following genes TRANK1, MAD1L1, PIK3C2A, IFI44L. Four have been previously implicated in either SCZ (MHC, MAD1L1) (12, 19) or BP (TRANK1, IFI44L) (41) but the association near PIK3C2A (chr11:17023194-17381287) is novel (Supplementary Figures 1a-f). The region of LD around this SNP includes RPS13, PIK3C2A, NUCB2, KCNJ11, and ABCC8. This locus has not been previously identified through GWAS but has recently been implicated using an alternative approach (42). None of the six genome-wide significant SNPs identified here demonstrated significant heterogeneity in odds ratios between BP and SCZ although MHC had the largest difference in effect size and approached significance (BP OR=0.88, SCZ OR=0.80, p=0.059). However, this test is probably underpowered in meta-analyses of only a few studies (43).
