Dopamine D2 Receptor Gene Taq1 A Polymorphism Is Associated with Cognitive Performance in Elderly Males without Dementia

Abstract

Objective: Dopaminergic function has been implicated in cognitive function. The objective of this study was to explore the association of the functional dopamine D2 receptor (DRD2) Taq1 A polymorphism (rs1800497) and cognitive performance in the male elderly without dementia. Method: We genotyped homogeneous population of ethnic Han Chinese aged male Taiwanese (N = 192) for the DRD2 Taq1 A polymorphism, and assessed them with a comprehensive neuropsychological measurement (Cognitive Abilities Screening Instrument Chinese version, CASI C-2.0) and the Wechsler Digit Span Task tests. The genotypic group differences of the DRD2 Taq1 A polymorphism in CASI cognitive profiles and the Wechsler Digit Span Task test were examined. Results: Subjects with DRD2 Taq1 A1/A2 and A2/A2 genotypes had significantly higher total CASI scores than those with A1/A1 genotype (p = 0.013). Of the nine domains of CASI, ”orientation” and ”short term memory” were found to be significantly associated with the DRD2 genotypes (p = 0.015 and 0.035, uncorrected). No genetic effect for this polymorphism was found in the Digit Span Task tests. Conclusion: In this study, we found that a nominal association existed between DRD2 Taq1 A polymorphism and CASI scores, particularly in the ”orientation” and ”short term memory” domains. The results suggest that the DRD2 Taq1 A polymorphism plays a role in specific cognitive functions in the normal male elderly Taiwanese.