Department of Psychiatry, Taipei Veterans General Hospital, Taiwan, ROC.
Dement Geriatr Cogn Disord. 2011;32(3):159-63. doi: 10.1159/000333074. Epub 2011 Oct 13.
Aging is associated with cognitive deterioration, and genetic factors are implicated in individual cognitive differences in the aged. The C677T mutation in the 5,10-methylenetetrahydrofolate reductase gene (MTHFR) yields a common thermolabile variant (T) with reduced enzyme activity and consequent elevation of serum homocysteine concentrations. We designed the present study to investigate whether this functional polymorphism may affect global and specific cognitive functions in older Chinese males without dementia.
The subjects included 356 elderly males without major psychiatric disorders or dementia, who were assessed by the Cognitive Abilities Screening Instruments (CASI) and the Wechsler Digit Span Task tests.
A significant association was found between the MTHFR C677T polymorphism and total CASI scores (p = 0.012), particularly in short-term memory (p = 0.002) and concentration/mental manipulation (p = 0.007). Post hoc tests indicated that the C/T heterozygotes achieved better cognitive function test results than C/C or T/T carriers. No association was found between the MTHFR genotype and the Wechsler Digit Span Task tests.
These results suggest that a heterozygote advantage exists for the MTHFR C677T polymorphism in specific cognitive functions in elderly Chinese males without dementia.
衰老与认知能力下降有关，个体的认知差异与遗传因素有关。5,10-亚甲基四氢叶酸还原酶基因（MTHFR）的 C677T 突变产生了一种常见的热不稳定变异体（T），其酶活性降低，导致血清同型半胱氨酸浓度升高。本研究旨在探讨这种功能性多态性是否会影响无痴呆的中国老年男性的整体和特定认知功能。
本研究纳入了 356 名无重大精神障碍或痴呆的老年男性，通过认知能力筛查工具（CASI）和韦氏数字跨度任务测试对其进行评估。
MTHFR C677T 多态性与 CASI 总分显著相关（p=0.012），特别是在短期记忆（p=0.002）和注意力/心理操作（p=0.007）方面。事后检验表明，C/T 杂合子的认知功能测试结果优于 C/C 或 T/T 携带者。MTHFR 基因型与韦氏数字跨度任务测试之间无关联。
这些结果表明，无痴呆的中国老年男性中，MTHFR C677T 多态性在特定认知功能方面存在杂合子优势。
