MTHFR gene polymorphism as a risk factor for diabetic nephropathy and macrovascular disease in NIDDM patient

Shin, Jong Sung; Oh, Kwang Sik; Kwon, Soon Kil; Ji, Jeong Hoon; Lee, Tae Won; Park, Young Sun; Kim, Mi Sung; Koong, Seong Su; Oh, Tae Geun

Abstract

BACKGROUND: Diabetic nephropathy develops in 20-30% of patients with non-insulin dependent diabetes mellitus (NIDDM). Poor glycemic control, hypertension and duration of diabetes are known as risk factors for the development of diabetic nephropathy and there is high prevalence of diabetic nephropathy in the patients who have familial history of diabetic nephropathy, so it has been assumed that genetic factor is associated with the background of its occurences. Recently it has been observed that a cytosine to thymidine substitution of the methylenetetrahydrofolate reductase (MTHFR) gene at nucleotide 677 (C677T) was related to diabetic nephropathy in patients with NIDDM and MTHFR gene polymorphism was also known to predispose to vascular disease. This study was performed to investigate whether MTHFR gene polymorphism is associated with the development of diabetic nephropathy and macrovascular disease in NIDDM patients.
METHODS
The study population consisted of 243 NIDDM patients (duration> OR = 10 years). Nephropathy was defined by 24 hour urinary protein excretion of more than 500 mg. The MTHFR gene fragment was extracted using the polymerase chain reaction. The presence of the mutation was identified by HinfI digestion, which cuts at the mutation site, followed by 2.5% metaphore agarose electrophoresis and ethidium bromide staining. Statistical differences in genotype distribution and allele frequencies among the groups were assessed by the chi-square test.
RESULTS
There was no difference in clinical characteristics except the prevalence of hypertension and diabetic retinopathy between nephropathy group and non-nephropathy group. The data do not show any difference of genotype distribution or allele frequencies between patients with or without diabetic nephropathy and macrovascular disease
CONCLUSION
With the above results, it is assumed that there are no significant relationships among MTHFR gene polymorphism, diabetic nephropathy, and macrovascular disease.