SNPs in the OCD-associated set and the null matched SNP sets were annotated both with cis-eQTL status and with the genes they regulate (i.e., eGenes) in brain and immune tissues. The enrichment p-value was calculated as the proportion of randomized sets in which the number of eGenes matched or exceeded the observed count among trait-associated SNPs. If multiple variants implicated the same eGene in a tissue or cell type, the eGene was counted only once. This strategy is different from counting individual eQTLs variants, as was done for the previous OCD GWAS (Stewart et al. 2013), where multiple SNPs may be regulating the same gene, while here all eQTLs targeting the same gene are counted only once. We also performed “pan-tissue” eQTL eGene analysis by combining the eQTL results from all the brain tissue subtypes and all the immune tissue and cell subtypes. If an eGene was present in more than one tissue, it was counted only once. To exclude the possibility of eQTL enrichment overestimation due to the gene-rich MHC region, we performed eQTL enrichment analysis both including and
