AbstractDownregulation of oligodendrocyte‐related genes in postmortem brains of patients with schizophrenia has been reported by several DNA microarray studies. We recently reported that enhanced DNA methylation of SOX10, which encodes a transcription factor responsible for terminal differentiation of oligodendrocyte, correlated with lower expression of SOX10 and other oligodendrocyte‐related genes. Although we ruled out the possible role of SNPs of SOX10 in the altered expression and epigenetic status of oligodendrocyte genes by mutation screening of the SOX10 gene, it is not known whether its genetic polymorphisms contribute to susceptibility to schizophrenia. Here we performed a case‐control and family‐based association study of SOX10 in Japanese patients with schizophrenia using six SNPs and one microsatellite marker. None of these markers showed significant associations with schizophrenia by case‐control or family‐based association study. Haplotype analysis did not reveal significant associations between the two groups. We concluded that genetic variations in the SOX10 gene do not contribute to susceptibility to Japanese schizophrenia. © 2006 Wiley‐Liss, Inc.