多巴胺 D2 受體 Taq1 A 基因多型性與健康老年男性認知功能之相關研究

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

目的：年紀老化造成的認知退化是一個常見的老年人問題，但年齡老化的認知功能下降有很大的個別差異，此差異與個體基因變異有相當關係，此外多巴胺的活性也會影響認知功能 · 故本研究探討多巴胺 D2受體功能性基因多型性 《 DRD2 Taq1A ）與正常老年男性的認知功能之相關性 · 方法：我們收集192位來自單一榮民之家未罹思失智症之老年男性，個別施以「認知能力飾檢工具」(Cognitive Abilities Screening Instrument Chinese version; CASI C-2.0)和「魏氏數字廣度測驗」(Wechsler Digit Span Task tests)及 DRD2 Taq1 A基因多型性鑑定。統計分析個案整體及分項認知測驗結果與 DRDz TaqlA 基因多型性之相關性，結果： 192 位個案平均年齡 80 . 0 (SD 5.0)歲，平均教育年數 5 . 2 (SD 4.6)年，平均CASI認知測驗分數85 . 9 (SD 10.3)分。三組 DRD2 Taq1 A基因型比較顯示DRD2 Taq1 A2 /A2 與 AI / A2基因型之個案，在 CASI之總體得分顯著較 Al / A1基因型之個案為高(p = 0.013)；此一趨勢亦在 CASI 分項測驗之「定向感」和「短期記憶」項目達到顯著性（ p = 0.015, 0.035，未矯正多重分析）。結論：本研究顯示多巴肢 D2受體 Taql 基因多型性會影響正常老年男性的認知功能表現，特別是在定向感和短期記憶之功能，Taql 基因多型性是否會影響老年女性之定向感或老年精神患者定向感或短期記憶障礙，值得進一步探討。

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 profi les and the Wechsler Digit Span Task test were examined. Results: Subjects with DRD2 Taq1 A1/A2 and A2/A2 genotypes had signifi cantly 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 signifi cantly 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 specifi c cognitive functions in the normal male elderly Taiwanese.