Polymorphisms in the promoter region of the basic fibroblast growth factor gene and proliferative diabetic retinopathy in Caucasians with type 2 diabetes

Background: Basic fibroblast growth factor (bFGF) expression is implicated in proliferative diabetic retinopathy (PDR). The aim of this study was to investigate the association of genetic polymorphisms (-553T/A, -834T/A and -921C/G) in the promoter region of the bFGF gene with PDR in patients with type 2 diabetes. The second aim was to determine whether serum levels of bFGF are affected by genetic factors. Methods: In this cross-sectional case-control study 313 unrelated Caucasians (Slovene population) with type 2 diabetes mellitus were enrolled: 206 patients with PDR and the control group of 107 subjects with type 2 diabetes of duration of more than 10 years who had no clinical signs of diabetic retinopathy. We analysed serum bFGF levels in 78 subjects with type 2 diabetes and 25 subjects without diabetes. Results: The AT genotype of the -553T/A polymorphism was present in 31 (15.0%) PDR patients and in seven (6.5%) controls (P = 0.03, odds ratio = 2.0, 95% confidence interval = 1.0-3.9). The AT genotype of the -834T/A polymorphism was present in 12 (5.8%) PDR patients and in 15 (14.0%) controls (P = 0.01, odds ratio = 0.4, 95% confidence interval = 0.2-0.8). Significantly higher bFGF serum levels were demonstrated in diabetics with the AT genotype of the -553 polymorphism compared with diabetics with the TT genotype, whereas the -834 and -921 polymorphisms failed to affect serum bFGF levels. Conclusions: We may conclude that the AT genotype of the 553 T/A polymorphism was associated with PDR in Caucasians with type 2 diabetes, therefore it might be used as a genetic marker of PDR in Caucasians, whereas carriage of the AT genotype of the -834 T/A polymorphism might decrease PDR risk.