DRD2 genotypic and haplotype variation is associated with improvements in negative symptoms after 6 weeks' amisulpride treatment

The aim of this study was to identify the association between the rs1079597 and rs1800497 genetic polymorphisms of the gene encoding the dopamine D 2 receptor (DRD2) protein and the treatment response to the selective dopamine receptor antagonist amisulpride. After 6 weeks of treatment with amisulpride, 125 schizophrenia patients were interviewed based on the Positive and Negative Syndrome Scale and the Clinical Global Impression-Severity Scale. Genotyping for rs1079597 and rs1800497 was performed using the TaqMan single nucleotide polymorphism genotyping assay. There were significant differences in the genotype frequency of the recessive model (χ 2 = 5.73, P = 0.017) and allele frequency (χ 2 = 5.16, P = 0.023) of rs1079597 between the responders and nonresponders based on the Positive and Negative Syndrome Scale negative symptoms scores. There was no significant finding in this regard for the rs1800497 polymorphism. The T-C and C-C haplotype of rs1079597-rs1800497 were associated with the negative symptom treatment response to amisulpride after permutation test. To the best of our knowledge, this is the first report of the positive finding in the association study between rs1079597 polymorphism and the treatment response to amisulpride in schizophrenic patients. A larger scale study involving more single nucleotide polymorphisms of DRD2 will progress the research into the pharmacogenetics of the treatment response to amisulpride.