A Preliminary Study on NPHS2 Gene Polymorphism (R229Q) in Diabetic Nephropathy Patients from South India

Podocin have been identified in childhood onset focal segmental glomerulosclerosis, but have not been well characterised in diabetic kidney disease. Aim: The present study was aimed to investigate the role of R229Q polymorphism of NPHS2 gene in type 2 diabetic patients with and without nephropathy from Andhra Pradesh, south India. Methodology: We enrolled a total of 300 diabetic patients with nephropathy (150) and without nephropathy (150) to screen for R229Q polymorphism. Genotyping of the SNP was carried out by PCR-RFLP method. Results: Overall frequency of the mutant allele A was found to be 0.24 in patients with type 2 diabetes and 0.30 in those with diabetic nephropathy, suggesting a lack of association of this polymorphism with susceptibility to diabetic nephropathy. Furthermore, patients carrying the mutant genotypes (GA, AA) with elevated levels of HbA1c were found to have poor kidney function parameters, illustrating the role of this polymorphism in the severity of diabetic nephropathy. Conclusion: This is the first report from Andhra Pradesh, India pertaining to R229Q polymorphism of NPHS2 gene in type 2 diabetes. We put forth the notion that R229Q polymorphism of NPHS2 is influential in the severity of diabetic nephropathy rather than its susceptibility. Individuals with poor glycemic control and R229Q mutant genotype are at a higher risk of developing nephropathy in the studied population. This study has significance in the increasing scenario of diabetes and its complications. Large scale studies are needed that will shed light on gene and environment interactions and the role of this polymorphism in the severity of disease.