Association of Single-Nucleotide Polymorphisms in the Cannabinoid Receptor 2 Gene with Schizophrenia in the Han Chinese Population

Cannabinoid receptor 2 (CNR2) is a major receptor in the endogenous cannabinoid system. In recent years, many studies have shown that the receptor is closely associated with schizophrenia. This study examined the relationship between CNR2 gene polymorphisms (rs2501432C/T, rs2229579C/T, rs2501401G/A) and schizophrenia. Three hundred sixteen schizophrenia patients and 334 healthy subjects were recruited as case and control groups, respectively. For rs2501432, the CT/TT genotype frequencies in the dominant model, TT genotype frequencies in the additive model, and T allele frequencies of the case group were lower than the control (P < 0.05), and the CT and TT genotypes and T allele frequencies of the male case group were significantly lower than the control (P < 0.05). For rs2229579, the T allele frequencies of the case group were higher than the control (P < 0.05). The T-C-G haplotype in the case group had a significantly lower frequency compared with the controls, but the T-T-A haplotype frequencies were higher in the case group than in the controls (P < 0.05). Our results suggest that the T allele of rs2501432 may be a protective factor, particularly in males, but the T allele of rs2229579 may be a risk factor for schizophrenia. T-C-G may be a protective haplotype for schizophrenia, but not the T-T-A haplotype.