We performed resequencing analysis of ZIC2 in 278 patients with schizophrenia who were of Japanese descent. The diagnosis of schizophrenia including the samples below was made on the basis of Diagnostic and Statistical Manual of Mental Disorders criteria (DSM-IV), by at least two expert psychiatrists. We then determined the allele frequencies of detected mutations using an expanded sample panel of schizophrenia patients (967 subjects: 457 men, 510 women; mean age 47.3 ± 13.8 [SD] years) and 1060 controls (502 men, 558 women; mean age 47.7 ± 13.6 years) who were documented as being free of mental disorders following brief interviews by expert psychiatrists. Our recruitment of schizophrenia and control subjects did not involve structured or semi-structured instruments. This study was approved by the ethics committees of RIKEN.