There was no evidence found for genome-wide significant association with OCD in either previously identified putative linkage regions (Supplementary Table S3) or in 22 previously identified candidate genes when examining the trio, case-control and trio-case-control groups. The Q-Q plot of candidate gene SNPs for the case-control group showed little inflation (λ=1.085, Supplementary Figure S8), suggesting no evidence for over-representation within these genes. While the Q-Q plot of the combined trio-case-control sample indicated small inflation (λ=1.168, Supplementary Figure S8), the follow-up enrichment test demonstrated no over-representation of top hits (p<0.001 and p<0.01) within previously identified candidate genes (p=0.15 and p=0.10, respectively). For the 22 OCD candidate genes examined, the lowest SNP p-values are reported in Supplementary Table S4. The strongest finding was observed for ADARB222, with a p-value=1.6×10-4, which did not survive correction for multiple testing of candidate gene SNPs (corrected p=0.53).
