Polymorphism of vascular endhothelial growth factor (VEGF) gene insertion/ deletion -2549 as risk factor of diabetic retinophathy in Javanese patients with type 2 diabetes
Diabetic retinopathy (DR) is a visual disorder caused by the diabetic microvascular complications. Genetic polymorphism in the vascular endothelial growth factor (VEGF) gene plays an importan role in the susceptibility of DR. The aim of this study was to evaluate the association of the polymorphism of VEGF gene insetion/deletion (I/D) -2549 with DR in Javanese type 2 diabetes mellitus (DM) patients. This was a case control study involving 40 Javanese type 2 DM patients with DR as case subjects and 40 Javanese type 2 DM patients without DR as control subjects. Type 2 DM patients with DR were recruited from Eye Polyclinic, whereas type 2 DM patients without DR were recruited from Endocrine Polyclinic of Dr. Sardjito General Hospital, Yogyakarta. Genotyping of VEGF gene I/D-2549 was conducted using PCR-RFLP method. Plasma VEGF levels were measured using Enzym-Linked Immunosorbent Assay (ELISA). The genotype distribution of DD (67.5%) and the allele frequency of D (82.5%) in type 2 DM patients with DR was higher than those without DR (27.5% for DD genotype and 56.3% for D allele). The OR of DD and ID genotypes versus II genotype between type 2 DM patients with DR and without DR was 6.882 (95%CI: 0.789-60.060; p=0.048), whereas OR for the D allele versus I allele between type 2 DM patients with DR and without DR was 3.667 (95%CI: 1.773-3.667; p=0.000). The plasma VEGF levels of DD genotype (92.16±49.73 pg/mL) were significantly higher than ID genotype (42.70±33.29 pg/mL) in type 2 DM patients (p=0.000). In conclusion, the polymorphism of VEGF gene I/D -2549 is associated with DR in Javanese type 2 DM patients. The DD genotype and D allele of the VEGF gene polymorphism are the risk factor of DR in those patients. The association of the polymorphism of VEGF gene with DR may be explained with the high plasma VEGF level. Keywords: vascular endothelial growth factor (VEGF) - polymorphism - diabetes - retinopathy - Javanese patients