Pharmacogenetics of tardive dyskinesia in schizophrenia: The role of<i>CHRM1</i>and<i>CHRM2</i>muscarinic receptors

Abstract

<b>Objectives:</b> Acetylcholine M (muscarinic) receptors are possibly involved in tardive dyskinesia (TD). The authors tried to verify this hypothesis by testing for possible associations between two muscarinic receptor genes (<i>CHRM1</i> and <i>CHRM2</i>) polymorphisms and TD in patients with schizophrenia.<b>Methods:</b> A total of 472 patients with schizophrenia were recruited. TD was assessed cross-sectionally using the Abnormal Involuntary Movement Scale. Fourteen allelic variants of <i>CHRM1</i> and <i>CHRM2</i> were genotyped using Applied Biosystems amplifiers (USA) and the MassARRAY System by Agena Bioscience.<b>Results:</b> The prevalence of the rs1824024*GG genotype of the <i>CHRM2</i> gene was lower in TD patients compared to the group without it (χ2 = 6.035, <i>p</i> = 0.049). This suggested that this genotype has a protective effect for the development of TD (OR = 0.4, 95% CI: 0.19-0.88). When age, gender, duration of schizophrenia and dosage of antipsychotic treatment were added as covariates in regression analysis, the results did not reach statistical significance.<b>Conclusions:</b> This study did identify associations between <i>CHRM2</i> variations and TD; the results of logistic regression analysis with covariates suggest that the association is, however, likely to be secondary to other concomitant factors.