Synergistic effects of the MTHFR C677T and A1298C polymorphisms on the increased risk of micro- and macro-albuminuria and progression of diabetic nephropathy among Iranians with type 2 diabetes mellitus

Objectives: To find whether polymorphisms of methylenetetrahydrofolate reductase (MTHFR) C677T and A1298C are risk factors for diabetic nephropathy (DN) among type 2 diabetes mellitus (T2DM) patients from Western Iran. Design and methods: The MTHFR polymorphisms were detected in 72 microalbuminuric, 68 macroalbuminuric and 72 normoalbuinuric T2DM patients by PCR-RFLP. Results: The possession of both MTHFR 677T and 1298C alleles increase the risk of microalbuminuria to 4.3-fold (p = 0.007) in 12DM patients. The presence of either MTHFR 677T, 1298C allele is sufficient to increase the risk of macroalbuminuria in T2DM patients by 4.1 and 5.5 times (p = 0.027, and p = 0.006, respectively). The concomitant presence of both 677T and 1298C alleles act in synergy to increase the risk of macroalbuminuria by 20.4-fold (p<0.001) and progression of DN from microalbuminuria to macroalbuminuria (OR=4.73, p=0.01). Conclusion: Both MTHFR 677T and 1298C alleles increased the susceptibility to the onset and progression of DN in Iranians with T2DM. (C) 2010 The Canadian Society of Clinical Chemists. Published by Elsevier Inc. All rights reserved.