No association between dopamine D3 receptor gene Ser9Gly polymorphism and tardive dyskinesia in schizophrenia

Objective: Tardive dyskinesia (TD) is a long-term adverse effect of antipsychotic drug use. Ser9Gly polymorphism of the dopamine 3 receptor (DRD3) has been shown to affect dopamine binding affinity, and may contribute to the susceptibility of antipsychotic-induced TD. This study investigated the possible association between DRD3 gene variant and TD. Methods: We evaluated whether a DRD3 Ser9Gly polymorphism is associated with antipsychotic-induced TD in 209 Korean schizophrenia patients with (n=83) and without TD (n=126) who were matched for antipsychotic drug exposure and other relevant variables. Results: There was no significant association between genotype and allele frequencies determined by the Ser9Gly polymorphism of DRD3 between TD and non-TD patients. In addition, there was no significant difference in terms of total Abnormal Involuntary Movement Scale scores among the three genotype groups. Conclusion: Within the limitations imposed by the size of the clinical sample, these findings suggest that the Ser9Gly polymorphism of DRD3 does not contribute significantly to the risk of TD.