Aim:To investigate the possible association of the CYP2D6 gene C100T poly-morphism and the CYP1A2 gene C163A polymorphism with tardive dyskinesia(TD)in Chinese patients with schizophrenia.Methods:The recruited schizo-phrenic patients were assessed with the Abnormal Involuntary Movement Scale(AIMS),and divided into groups with TD(n=91) and without TD(n=91)accord-ing to the AIMS score.Polymorphisms of the CYP2D6 and CYP1A2 genes weredetermined by polymerase chain reaction(PCR)-restriction fragment length poly-morphism(RFLP).Results:No allele frequencies deviated from Hardy-Weinbergequilibrium.No significant differences in genotypes frequencies of the CYP2D6C100T polymorphism were observed between patients with TD and without TD(X~2=4.078,P>0.05),but patients with TD had a significant excess of the T allelecompared with those without TD(X~2=4.28,P<0.05).Moreover,the frequency ofthe CYP1A2 C allele in patients with TD was significantly higher than that in thosewithout TD(x~2=6.38,P<0.05).An association between TD and the CYP2D6 100Tand CYP1A2 163C alleles was observed.Additionally,there were no differences inthe mean AIMS scores among different genotypes in TD patients as a group or insmokers.The results of logistic regression analysis demonstrated that mean ageand duration of illness were risk factors for TD,but not sex,cumulative exposureto neuroleptic drugs in years,CYP2D6 or CYP1A2 genotype.Conclusion:TheC100T polymorphism of the CYP2D6 gene and the C163A polymorphism of theCYP1A2 gene may be associated with neuroleptic drug-induced tardive dyskine-sia in Chinese patients with schizophrenia.However,genetic factors have a weakerassociation with susceptibility to TD compared with mean age and duration of illness.
