Abstract
Purpose: :
Vascular endothelial growth factor (VEGF) plays an important role in the development of diabetic retinopathy. The vitreous VEGF concentration is high in patients with diabetic retinopathy and VEGF expression is high in diabetic retina. Single nucleotide polymorphisms (SNPs) of VEGF gene have been shown to influence VEGF expression. We studied the association of VEGF SNPs with severity of diabetic retinopathy.
Methods: :
The study population consisted of 129 diabetic (type 1 or type 2) patients with laser–treated retinopathy, 99 diabetic patients with mild or no retinopathy and 524 non–diabetic controls. SNPs were genotyped for VEGF –2578A>C (rs699947), –634G>C (rs2010963) and +936C>T (rs3025039) using the 5' nuclease assay for allelic discrimination (TaqMan). The allele and genotype frequencies were analyzed with chi–square test in SPSS and the haplotype effect analysis was performed with the Thesias program.
Results: :
The mean diabetes duration was similar in patients with laser–treated retinopathy and in patients with mild or no retinopathy (22.8 vs. 22.7 years, respectively), but the laser–treated diabetic group had somewhat poorer glycemic control (9.2 vs. 8.4 %). The distribution of genotypes and the allele frequencies did not differ significantly between the diabetics and controls, between patients with laser–treated retinopathy and patients with mild or no retinopathy, or between patients with proliferative retinopathy and patients with non–proliferative retinopathy. Among the six haplotypes reconstructed of the studied SNPs based on the tight linkage disequilibrium at positions –2578, –634 and +936, no haplotype was associated with severity of diabetic retinopathy.
Conclusions: :
In conclusion, these findings suggest that VEGF polymorphisms –2578 A>C, –634 G>C and +936C>T are not associated with the severity of diabetic retinopathy.
Keywords: diabetic retinopathy • genetics