The role of glucocorticoid receptor gene (NR3C1) polymorphism on relapsing of idiopathic nephrotic syndrome in children

The Role of Glucocortikoid Receptor Gene (NR3C1 gene) Polymorphism on Relapsing of Idiopathic Nephrotic Syndrome in Children Aim : The objective of this study is to investigate the effect of glucocorticoid receptor gen (NR3C1 gen) polymorphism on steroid response and development of relapses in childhood idiopathic nephrotic syndrome. Material and Methods : In this prospective study, it's included 40 patients following with a diagnosis of idiopathic nephrotic syndrome in Pediatric Nephrology Department of Cukurova University Hospital between the years of 1996 and 2012. 20 patients were treated for frequent relapsing NS and the other group of 20 patients were following with no relapses from the beginning of the first treatment since 5 years. Demographic characteristics, family story and laboratory findings (BUN, creatinine, total protein, albumin, total cholesterol, C3, C4) analyzed at the beginning of the first diagnosis and treatment were recorded. 2 cc blood samples were taken in EDTA-containing tubes from each patient for DNA isolation. We performed 3 known single nucleotide polymorphisms (SNPs) (N363S, ER22/23EK, I559N) of the glucocorticoid receptor gene (NR3C1 gene) in patients and healthy control groups. Results : The genotype distribution and allele frequencies of NR3C1 gene N363S, ER22/23EK, I559N SNPs were analyzed and revealed that; ER22/23EK SNPs genotype distribution was GG, N363S SNPs genotype distribution was AA and I559N SNPs genotype distribution was TT in all of the patients with idiopathic nephrotic syndrome and healthy control groups (% 100). For each SNPs, allele frequencies in both groups were the same (p=1,0). The study revealed that we did not see NR3C1 gene polimorphisms for all patients and control groups. Conclusion : There was no difference in any genotype or allotype distribution between patient groups and control groups, the genotypes of N363S, ER22/23EK, I559N SNPs were homogenous and similar. These findings suggest that; NR3C1 gene polimorphisms doesn?t play an important role on the response to glucocorticoid treatment and development of relapses in our patient and control groups. However, we need further studies those includes increasing number of patients and genotyping all single nucletide polymorphisms of NR3C1 gene to confirm the study and think about the population diversity of this gene polymorphisms. Key words : Nephrotic syndrome, NR3C1 gene, relapsing NS, single nucleotide polymorphisms (SNPs).