Objective: The current study aimed to explore the association of single nucleotide polymorphisms (SNPs) within catechol-O-methyltransferase  (COMT ) and dopamine receptors with schizophrenia and genetic association with risperidone treatment response.
Methods: A total of 690 schizophrenic patients (case group) were selected and 430 healthy people were included as the controls. All patients received risperidone treatment continuously for 8 weeks. Next, peripheral venous blood samples were collected and were subjected to polymerase chain reaction-restriction fragment length polymorphism to amplify and genotype the SNPs within COMT  and dopamine receptors. Then, correlation analysis was conducted between Positive and Negative Syndrome Scale improvement rates and SNPs within COMT  and the dopamine receptor gene.
Results: The allele of DRD1  rs11749676 (A) emerged as a key element in reducing schizophrenia risk with statistical significance (P <0.001). Remarkably, alleles of COMT  rs165774 (G), DRD2  rs6277 (T), and DRD3  rs6280 (C) were associated with raised predisposition to schizophrenia (all P <0.001). Regarding DRD1  rs11746641, DRD1  rs11749676, DRD2  rs6277, and DRD3  rs6280, the case group exhibited a lesser frequency of heterozygotes in comparison with wild homozygotes genotype (all P <0.001). SNPs (COMT  rs4680, DRD2  rs6275, DRD2  rs1801028, and DRD2  rs6277) were remarkably associated with improvement rates of PANSS total scores (P <0.05). SNPs (COMT  rs165599 and DRD2  rs1801028) were significantly associated with risperidone efficacy on negative symptoms (P <0.05).
Conclusion: COMT  SNPs and dopamine receptor SNPs were correlated with prevalence of schizophrenia and risperidone treatment efficacy of schizophrenia.
Keywords: schizophrenia, catechol-O-methyltransferase, dopamine receptor gene, single nucleotide polymorphisms, risperidone