Association Between Polymorphisms of the Complement 3 Gene and Schizophrenia in a Han Chinese Population

Background/Aims: Schizophrenia is a severe psychiatric disorder, and complement 3 (C3) is closely related to schizophrenia. We investigated the association between C3 polymorphisms and schizophrenia in a Northeast Han Chinese population. Methods: A total of 2240 Chinese people, consisting of 1086 patients with schizophrenia and 1154 healthy controls, were recruited for this study. Ten single nucleotide polymorphisms (SNPs; rs11569562, rs344555, rs2241393, rs2241392, rs11569514, rs445750, rs451760, rs11672613, rs2230205, and rs2250656) in C3 were selected and genotyped. Results: Genotype distribution analysis indicated that rs11569514 was significantly associated with schizophrenia. In the dominant model (AA vs. GG+GA genotypes), we found a significant protective effect for rs344555 against schizophrenia (odds ratio [OR]: 0.72, 95% confidence interval [CI]: 0.53–0.99, P = 0.04). In the codominant model (TT vs. AA), we found a significant risk effect for rs11569514 on schizophrenia (OR: 4.39, 95% CI: 2.06–9.37, P < 0.001). Haplotypes, including TG (rs11569562 and rs344555), TGG (rs11569562-rs344555-rs2241393), AG (rs344555-rs2241393), CGGGT (rs11569562-rs344555-rs2241393-rs2241392-rs11569514), and ACGTG (rs11569514-rs445750-rs451760-rs11672613-rs2230205), showed either a risk or protective role for schizophrenia. Conclusions: SNP rs11569514 in C3 and haplotypes of C3 variants were associated with schizophrenia in a Han Chinese population.