Methylenetetrahydrofolate reductase genetic polymorphisms in patients with cataract

PURPOSE: Hyperhomocysteinemia is commonly associated with polymorphisms in the methylenetetrahydrofolate reductase (MTHFR) gene. The level of homocysteine can be lowered by dietary intake of folate. A protective effect of folate supplementation has been reported against cataract. Here we investigate MTHFR polymorphisms in human cataract. DESIGN: Retrospective case,control association Study. METHODS: Patients with nuclear (n = 77), cortical (n = 155), posterior subcapsular (n = 119), and mixed (n = 151) cataract, and 1.87 controls were analyzed for the MTHFR 677C -> T and 1298A -> C polymorphisms using minisequencing technique. RESULTS: The wild-type MTHFR 677CC/1298AA genotype was strongly overrepresented among cataract cases (P = .003). This effect was most pronounced in the mixed cataract group (P <.001). Hyperhomocysteine mia-associated genotypes had similar frequencies in cataract and control groups. CONCLUSIONS: The previously reported protective effect of folate against cataract is not due to overrepresentation of hyperhomocysteinemia-associated MTHFR geno-types. Instead, the strong predominance of wild,type MTHFR in cataract may suggest impaired DNA synthesis as a cataractogenic factor.