Relationship of vascular endothelial growth factor (VEGF) +405 G/C polymorphism and proliferative retinopathy in patients with type 2 diabetes

Abstract

The role of the vascular endothelial growth factor (VEGF) gene polymorphism in proliferative diabetic retinopathy (PDR) is controversial. VEGF seems to play a central role in mediating microvascular pathology in proliferative diabetic retinopathy (PDR). Recently, a +405 G/C VEGF polymorphism was shown to be associated with PDR. The aim of the current study was to evaluate whether the VEGF gene polymorphism is an independent risk factor for severity of diabetic retinopathy in an Iranian adult population. A total of 119 consecutive patients with PDR (group A) and 279 patients with nonproliferative diabetic retinopathy NPDR (group B) were studied. Patients were recruited from the eye clinic of Ahvaz Jondi Shapour University of Medical Sciences between January 2007 and April 2009. After extraction of genomic DNA, genotyping of the +405 G/C polymorphism of the VEGF gene was performed by polymerase chain reaction (PCR) and restriction fragment length polymorphism (RFLP) analysis. Demographic, anthropometric, and plasma biochemistry data were recorded. In univariate analysis, the groups were statistically similar in all variables except for hemoglobin A1c (HbA1c) and +405 G/C polymorphism. The distribution of the GC genotype was significantly different in patients with PDR compared with NPDR. In a multivariate logistic regression analysis (using sex and body mass index as clinically significant variables and HbA1c and genotype as statistically significant variables) was then used to determine independent associations and adjusted odds ratios (ORs), the GG genotype (compared with the CC genotype) was an independent predictor of PDR [OR = 1.87, 95% confidence interval (CI) =1.034-3.383 P = 0.039]. The HbA1c was more common in the PDR group (P = 0.004); in a multivariate regression, the association remained significant (OR = 1.194, 95% CI = 1.056-1.350, P = 0.005). These findings suggest that the VEGF +405 GG polymorphism might be associated with the risk of proliferative diabetic retinopathy in an Iranian population.