| Abstract | Tardive dyskinesia (TD) occurs in approximately 20% of patients exposed to long-term antipsychotic treatment and may be influenced by genetic predisposition, in addition to clinical risk factors. In this study, we implemented a two-step approach to identify susceptibility genes for TD. First, we performed a secondary analysis of the Clinical Antipsychotic Trials of Intervention Effectiveness (CATIE) genome-wide association study (GWAS) dataset to identify candidate genes for TD severity. A total of 327 schizophrenia patients treated with antipsychotics who participated in the CATIE trial were included in a TD severity GWAS (approximately 495,000 SNPs). Cases were defined as demonstrating involuntary movements of a mild degree in two or more body regions or of a moderate to severe degree in at least one body region on at least two separate evaluations, whereas controls were completely free of abnormal involuntary movement on all evaluations. Using logistic regression and controlling for population stratification and relevant clinical risk factors, none of the associated SNPs reached GWAS significance; however, several promising SNPs were identified for follow-up investigation. In the second step, we performed an association study of the top 25 SNPs in an independent sample of 170 Jewish, Israeli, schizophrenia patients (retrospective, cross-sectional design). Association of the SNP rs3943552 T allele in the GLI2 gene with TD was observed in a subsample of Ashkenazi Jewish patients (N = 96, P = 0.018; P = 6.2 × 10?? in the CATIE sample). The GLI2 gene encodes a transcription factor that participates in the development of the dopaminergic system during embryogenesis. Taken together, our findings support a possible contribution of GLI2 to TD susceptibility. |