Our study population included 2090 cases and 4567 controls after quality control was completed. Among our cases, 60% were female, while 76% of controls were female. Based on Principal Component Analysis (PCA; Figure S2), we used the first six PCAs as covariates to adjust for variation in ancestry in all heritability analyses. As a check for compatibility of cohorts, we first estimated heritability by treating EGOS and NORDiC controls as cases and LifeGene-ANGI controls as controls. Heritability was estimated at 0.0001% (SE = 5%). These results show that the control cohorts were homogeneous. Next, we estimated heritability of OCD for the full sample, contrasting OCD cases to controls and yielding an estimate of 29% (SE=4%) for a population prevalence of 1%.
