Relationship between 936C/T polymorphism in 3’-untranslated region of vascular endothelial growth factor gene and diabetic retinopathy in China

AIM: To study the distribution of 936C/T polymorphism in 3’- untranslated region of vascular endothelial growth factor (VEGF) gene in Chinese Han population and to analyze the relationship between the polymorphism and diabetic retinopathy (DR). METHODS: Two hundred and fifty-four patients with type 2 diabetes mellitus recruited in this study were divided into NPDR group (non-proliferative diabetic retinopathy), PDR group (proliferative diabetic retinopathy) and DM (diabetes without retinopathy) group. The normal control group consisted of 120 subjects. Genotypes were identified by PCR-RFLP among all the subjects, while other clinical parameters were measured. Serum levels of VEGF were tested by the method of ELISA. RESULTS: The frequencies of both genotype CC and allele C were significantly higher in NPDR group and PDR group than those in NC group (²=9.934, ²=4.899, P<0.05 and ²=10.895, ²=5.714, P<0.05) and DM group (²=7.490, ²=4.448, P<0.05 and ²=8.333, ²=5.227, P<0.05). However, the frequencies of genotype (TT+CT) and allele T were significantly lower in NPDR group and PDR group than those in NC group (²=9.934, ²=10.895, P<0.01 and ²=4.899, ²=5.714, P<0.05) and DM group (²=7.490, ²=8.333, P<0.01 and ²=4.448, ²=5.227, P<0.05). Multivariate logistic regression analysis showed that the levels of glycohemoglobin(HbA1c), total cholesterol(TC),low-density lipoprotein cholesterol(LDL-C) and plasma VEGF presented a positive correlation with DR, respectively, and the 936C/T mutation of VEGF exhibited a negative correlation with DR (β=-1.027, OR=0.343, P<0.01, CI: 0.157-0.723). CONCLUSION: Allele 936C of VEGF may be a genetic marker susceptible to DR, while allele 936T may be a protective genetic marker of DR. The 936C/T mutation of VEGF may be a protective factor against DR.