The sample included 2,379 subjects from 1,009 small nuclear families (SNFs) and 7,586 unrelated individuals. Of the families, 747 (74%) had ≥2 members with a lifetime DSM-IV diagnosis of CD. In addition to the proband in each of the SNFs, there were 1,160 siblings, 169 parents, and 41 other family members. Additionally, 4,575 subjects with CD and/or OD and 3,011 controls (screened to exclude those with a lifetime substance use disorder) from case-control studies were included in the analysis. Pedigree information was obtained for all families in the study.
