Background: Osteopontin (OPN) C-443T promoter polymorphism has been shown as a genetic risk factor for diabetic nephropathy (DN) in type 2 diabetic patients (T2D).
Methods: In the present study we investigated the association of three functional promoter gene polymorphisms C-443T, delG-156G, and G-66T and their haplotypes with the risk of DN and estimated Glomerular Filtration Rate (eGFR) in Asian Indians T2D patients using Real time PCR based Taqman assay. A total of 1165 T2D patients, belonging to two independently ascertained Indian Asian cohorts, were genotyped for three OPN promoter polymorphisms C-443T (rs11730582), delG-156G (rs17524488) and G-66T (rs28357094).
Results: -156G allele and GG genotypes (delG-156G) and haplotypes G-C-G and T-C-G (G-66T, C-443T, delG-156G) were associated with decreased risk of DN and higher eGFR. Haplotype G-T-delG and T-T-delG (G-66T, C-443T, delG-156G) were identified as risk haplotypes, as shown by lower eGFR.
Conclusion: This is the first study to report an association of OPN promoter gene polymorphisms; G-66T and delG-156G and their haplotypes with DN in T2D. Our results suggest an association between OPN promoter gene polymorphisms and their haplotypes with DN.
Keywords: Osteopontin promoter gene polymorphism; diabetic nephropathy; eGFR; haplotypes; type 2 diabetes.