Association of VEGFA promoter polymorphisms rs699947 and rs35569394 with diabetic retinopathy among North-Central...

Diabetes mellitus type 2 is often described as the global pandemic of the 21^st century with India emerging as its capital. Microvascular complications such as retinopathy associated with diabetes are a serious world health problem, leading to the already existing burden of blindness. The aim of this study was to determine whether VEGF gene polymorphisms rs35569394 and rs699947 are associated with DR in North Indians.

North Indian subjects, diabetic controls with no retinopathy (DR I, n = 51), subjects with diabetes with mild-moderate retinal changes (DR II, n = 50), and subjects with diabetes with severe retinopathy with/without retinal neovascularization (DR III, n = 55) were recruited for this study. Genotyping of the VEGF gene I/D polymorphism was done by PCR and C/A polymorphism by PCR-RFLP method.

DD-genotype was 2.73 times over expressed among DR III category (p = .02; OR: 2.73; 95% CI: 1.20-6.19) as compared to DR I category among male subgroup. C-allele (rs699947) had 1.66-times more exposure among DR III as compared to DR I (C vs. A allele; p = .063; OR: 1.66; 95% CI: 0.97-2.84), probably due to high linkage disequilibrium between both the polymorphisms.

Results of our study support the hypothesis that D-allele and DD-genotype of rs35569394 have deleterious effect on the progression of DR. C-allele had skewed frequency towards DR III subjects owing to strong linkage disequilibrium between C-allele (rs699947) and D-allele (rs35569394).