Endothelial nitric oxide synthase (eNOS) VNTR as a probable marker in type 2 diabetes mellitus

Background: The gene encoding eNOS is located on chromosome 7q36, a genetic region previously linked to metabolic syndrome, cardiovascular and renal diseases. Generally, in diabetes there are numerous genes involved, each being a small contributor in type 2 diabetes mellitus (T2DM) manifestation. A 27 bp variable number of tandem repeat (27 bp VNTR-a/b) in intron 4 of eNOS gene has gained attention and this polymorphism may affect the expression of eNOS. We studied the association of eNOS-27 bp VNTR with T2DM in north Indian population. Material and methods: Blood samples were collected in 0.5 M EDTA from 200 T2DM patients and 210 age/sex matched healthy controls. Genomic DNA was extracted from peripheral blood mononuclear cells (PBMCs) using the salting out method. The 27-VNTR polymorphism was determined by standard PCR amplification using forward and reverse primers 5′-AGGCCCTATGGTAGTGCCTTT-3’ and 5′-TCTCTTAGTGCTGTGGTCAC-3’ respectively. The genotypes were determined by analyzing the amplified products on 2% agarose gels. Genotypic and allelic frequencies were calculated by SPSS (version 15.0). Results: Clinical and biochemical profiles of healthy controls and T2DM cases as well as gender wise comparisons showed significant association in certain parameters (P <0.001). Five different alleles (I, II, IV, V and VI) were found in the study population. The genotypic frequency was significantly associated with T2DM (P <0.001). Conclusion: A significant role of allele ‘I’ in T2DM susceptibility was an interesting observation. Therefore, The 27 bp VNTR in eNOS gene polymorphism can be used as a probable marker in determining susceptibility to T2DM in north Indian population.