The OCD sample consisted of 1,437 OCD cases and 290 parent-child trios. While the original GWAS sample consisted of 1865 OCD probands recruited from 21 sites in North, Central and South America, Europe, the United Arab Emirates, and South Africa, only subjects of European ancestry (EU, AJ, and EU-derived Afrikaner (SA) descent) were included in the current study (16). Co-occurring TS or CT was assessed in 77% of OCD probands; of these, 12% had co-morbid TS or CT (N=159). TS/CT status was unknown for 405 OCD-affected individuals.
