The distributions of genotypes for all investigated SNPs were checked for correspondence to the Hardy-Weinberg (H-W) equilibrium. In order to find potential relevance of the selected SNPs to schizophrenia, their allele and genotype frequencies (carriage rates) in patients and control subjects were compared. The calculations of allele and genotype frequencies were based on the observed number of genotypes. Estimated proportion of haplotypes and linkage disequilibrium (LD) between investigated loci were calculated using SNP analyzer software [26]. Maximum-likehood (ML) haplotype frequencies in patients and control subjects were estimated using an expectation-maximization (EM) algorithm [27]. The significance of differences between allele and genotype frequencies in both groups was determined using Pearson's Chi-square test. The odds ratio (OR), 95% confidence interval (CI), and Pearson's p-value were calculated. Statistical power of the present study was calculated according to the protocol described elsewhere [28]. P-values were adjusted by Bonferroni multiple correction approach [29], and those less than 0.05 were considered statistically significant.