Objective: To evaluate the role of methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms in Chinese patients with type 2 diabetes mellitus and diabetic nephropathy(DN).
Methods: 85 type 2 diabetes mellitus patients and 57 controls were recruited in the study. MTHFR genetic C677T polymorphism was determined with PCR-restriction fragment length polymorphisms (RFLP). Plasma total homocysteine level was measured using high-performance liquid chromatography (HPLC) with fluorescence detection.
Results: The frequency of MTHFR TT homogenetic type and CT heterogenetic type and allele T(28.21%, 51.28%, 53.85%) was significantly higher in type 2 diabetes mellitus with diabetic nephropathy group than those without nephropathy (19.57%, 28.26%, 33.70%) or normal controls (17.54%, 28.07%, 31.58%). However, there was no significant difference of MTHFR genotype and allele frequency between type 2 diabetes mellitus without nephropathy and normal controls. The presence of T allele appeared to have a stronger association with the development of diabetic nephropathy. The odds ratio was 2.30 and the 95% confidence interval was 1.24-4.26. Moreover, plasma homocysteine levels were markedly higher in patients with TT or CT genotype than those in patients with CC genotype.
Conclusions: MTHFR gene C677T mutation associated with a predisposition to increased plasma homocysteine levels may represent a genetic risk factor for diabetic nephropathy in Chinese type 2 diabetes mellitus.