Rage gene promoter polymorphisms and diabetic retinopathy in a clinic-based population from South India

Abstract

Purpose The main objective of this study was to evaluate if the 429T/C, 374T/A and 63 bp deletion polymorphisms in the RAGE gene are associated with diabetic retinopathy (DR) among Type 2 diabetic subjects in a clinicbased population from South India. Methods We screened 149 normal glucose tolerant subjects (NGT), 189 Type 2 diabetes subjects without retinopathy (DM) and 190 subjects with DR for these polymorphisms using the PCR-RFLP method. DR was diagnosed by grading color fundus photography. Logistic regression models were used to evaluate the association of individual polymorphisms with DR. Expectation– maximization algorithms were implemented in haplotype tests of association to examine the combined effects of 429T/C and 374T/A polymorphisms on DR. Results The allelic frequencies of 429T are 0.83 in NGT, 0.84 in DM and 0.85 in DR subjects, and that of 374T are 0.93 in NGT, 0.92 in DM and 0.88 in DR subjects. The 374 polymorphism was found to be associated with non-proliferative retinopathy when this subgroup was compared to the DM group (OR¼1.814, 95% CI¼1.005–3.273). However, this association was not obvious when both the subphenotypes of DR (the nonproliferative and proliferative DR groups) were studied jointly.We found no evidence for associations between the 429T/C polymorphism and the DR phenotype. Finally, extension to a 2-SNP haplotype did not reveal any significant statistical difference between the groups (P¼0.668). Conclusion In this study, we found a modest association with the 374T/A polymorphism in the nonproliferative DR subgroup.