Association of CYP2D6 and CYP1A2 gene polymorphism with tardive dyskinesia in Chinese schizophrenic patients

Aim: To investigate the possible association of the CYP2D6 gene C100T polymorphism and the CYP1A2 gene C163A polymorphism with tardive dyskinesia (TD) in Chinese patients with schizophrenia. Methods: The recruited schizophrenic patients were assessed with the Abnormal Involuntary Movement Scale (AIMS), and divided into groups with TD (n=91) and without TD (n=91) according to the AIMS score. Polymorphisms of the CYP2D6 and CYP1A2 genes were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP). Results: No allele frequencies deviated from Hardy-Weinberg equilibrium. No significant differences in genotypes frequencies of the CYP2D6 C100T polymorphism were observed between patients with TD and without TD (chi(2=)4.078, P > 0.05), but patients with TD had a significant excess of the T allele compared with those without TD (chi(2=)4.28, P < 0.05). Moreover, the frequency of the CYP1A2 C allele in patients with TD was significantly higher than that in those without TD (chi(2)=6.38, P < 0.05). An association between TD and the CYP2D6 100T and CYP1A2 163C alleles was observed. Additionally, there were no differences in the mean AIMS scores among different genotypes in TD patients as a group or in smokers. The results of logistic regression analysis demonstrated that mean age and duration of illness were risk factors for TD, but not sex, cumulative exposure to neuroleptic drugs in years, CYP2D6 or CYP1A2 genotype. Conclusion: The C100T polymorphism of the CYP2D6 gene and the C163A polymorphism of the CYP1A2 gene may be associated with neuroleptic drug-induced tardive dyskinesia in Chinese patients with schizophrenia. However, genetic factors have a weaker association with susceptibility to TD compared with mean age and duration of illness.