CG/CA genotypes represent novel markers in the NPHS2 gene region associated with nephrotic syndrome

Nephrotic syndrome (NS) is considered as a primary disease of the kidney that represents a heterogeneous group of glomerular disorders occurring mainly in children. It is generally divided into steroid-sensitive and steroid-resistant forms, depending upon the patient's response to steroid therapy. Among the genes involved, the NPHS2 gene has been reported as the causative gene in steroid resistant form of nephrotic syndrome. In the present study, heterozygosity rate, allelic frequency and linkage of rs2274625 and rs3829795 markers were investigated in the NPHS2 gene region. To determine the SNP alleles, tetra-primer ARMS PCR was used. After genotyping rs2274625 and rs3829795 polymorphic markers in 120 unrelated individuals and nine trios families, the data were analysed using various computer programs such as UCSC Genome Browser, dbSNP and SNPper. Based on the statistical analysis of the results, for rs2274625 marker, allele frequency for C and T alleles was 97% and 3%, respectively. For rs3829795 marker allele frequency for G and A alleles was 55% and 45%, respectively. The values of heterozygosity index for the examined markers were 5% for rs2274625 and 45/8% for rs3829795. Consequently, two informative haplotypes, CG/CA, were identified in the NPHS2 gene region through combination of these two markers. These haplotypes can serve as appropriate tools for the identification of heterozygous carriers and linkage analysis of nephrotic syndrome disease in the Iranian families with an affected child.