Methylenetetrahydrofolate reductase gene polymorphism as a risk factor fordiabetic nephropathy in IDDM patients

A missense mutation in the methylenetetrahydrofolate reductase gene (MTHFR) , C677T, results in a thermolabile variant with reduced activity, Elevated levels of homocysteine have been recognized as a risk factor for vascular d isease. Insulin-dependent diabetes mellitus (IDDM) is characterized by a hi gher prevalence of vascular complications. We analyzed the frequency of C67 TT MTHFR in IDDM and control groups. The genotype distribution did not diff er between control subjects (n = 297) and IDDM patients (n = 392) (chi(2) = 5.413, df = 2, P > 0.05). The MTHFR T677T genotype was found significantly more frequently in IDDM patients with diabetic nephropathy (0.216) compare d with the IDDM patients without nephropathy (0.056); the odds ratio was 2. 635 (95% CI 1.768-3.927). Thus, we suggest that the T677T genotype of the M THFR gene is an independent risk factor for diabetic nephropathy in IDDM. ( C) 1999 Academic Press.