Polymorphism of vascular endhothelial growth factor (VEGF) gene insertion/ deletion -2549 as risk factor of diabetic retinophathy in Javanese patients with type 2 diabetes

Abstract

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