We conducted a series of bioinformatic analyses that examined whether loci with shared risk effects on multiple neuropsychiatric disorders had characteristic features that distinguished them from non-pleiotropic risk loci. First, we annotated the functional characteristics of 146 lead SNPs using various public data sources (Online Methods; Tables S4). Overall, they showed significant enrichment of genes expressed in the brain (beta=0.123, SE=0.0109, enrichment p = 1.22×10−29) and pituitary (beta=0.0916, SE=0.0136, p = 8.74 × 10−12), but not in the other Genotype-Tissue Expression (GTEx) tissues. (Table S5.1; Fig. 5a). A separate analysis of 109 pleiotropic risk loci also showed specific enrichment of genes expressed in multiple brain tissues (p = 1.55 × 10−5; Table S5.2), while disorder-specific loci showed nominally enriched brain gene expression in the cortex (p =2.14 × 10−2; Table S5.3).
