Endothelial nitric oxide synthase VNTR (intron 4 a/b) polymorphism association with type 2 diabetes and its chronic complications.

Unlabelled: SUBJECT AND AIMS: Endothelial derived nitric oxide (eNOS) is involved in several functions playing important role in development of type 2 diabetes and insulin resistance. The aim of this study was to examine the association between eNOS intron 4 VNTR polymorphism and type 2 diabetes in an Iranian population.

Methods: A total of 220 patients with type 2 diabetes and 96 healthy control subjects were recruited from the same area. Genotyping was performed using PCR.

Results: A significant difference was found in genotype frequencies of eNOS polymorphism between patients and controls (aa+ab vs. bb p=0.02, OR 2.0 95% CI; 1.05-3.96). Also allele a frequency was significantly increased in patients with diabetes compared with controls (p=0.007, OR 2.1 95% CI; 1.19-4.08). We found that in patients with diabetic neuropathy the frequency of 'a' allele was significantly increased compared to the controls p=0.03, OR=1.8 95% CI (1.00-3.7). Both genotype and allele frequencies were significantly different between patients who were complication free compared to the controls [aa+ab vs. bb p=0.007, OR=2.6 95% CI (1.2-5.8) and p=0.001, OR=2.8 95% CI (1.4-5.9)] respectively with the a allele conferring the risk.

Conclusion: The association between eNOS VNTR polymorphism and T2DM seems to be stronger in patients without diabetic complications indicating diverse effect of eNOS polymorphism on diabetes and diabetic microvascular complications.