We also studied three series of other subjects, including 142 subjects with nonsyndromic autism spectrum disorders, 143 subjects with schizophrenia, and 190 healthy control subjects matched for ancestral origin. The subjects in all three series were mainly of French Canadian or European origin (for details regarding case definitions, see the Supplementary Appendix, available with the full text of this article at NEJM.org). Blood samples were obtained from all subjects and from each set of parents, after we had obtained written informed consent and approval from the ethics committee at each institution.
