The 33 novel loci discovered here encompass genes of expected biological relevance to BD, such as the ion channels CACNB2 and KCNB1. Amongst the 64 BD loci, 17 have previously been implicated in GWAS of schizophrenia60, and seven in GWAS of major depression61, representing the first overlap of genome-wide significant loci between the mood disorders. For these genome-wide significant loci shared across disorders, 17/17 and 5/7 of the BD index SNPs had the same direction of effect on schizophrenia and major depression, respectively (Supplementary Table 23). More generally, 50/64 and 62/64 BD loci had a consistent direction of effect on major depression and schizophrenia, respectively, considerably greater than chance (P < 1 × 10−5, binomial test). Bivariate gaussian mixture modeling estimated that across the entire genome, almost all variants influencing BD also influence schizophrenia and major depression, albeit with variable effects62. SNPs in and around the MHC locus reached genome-wide significance for BD for the first time. However, unlike in schizophrenia, we found no influence of C4 structural alleles or gene expression63. Rather the association was driven by variation outside
