The association between PON1 gene polymorphisms (Q192R and L55M) and nephrotic syndrome in Iraqi children

Abstract

Background: The role of paraoxonase 1 enzyme (PON1) and its single nucleotide polymorphisms (SNPs) in children with nephrotic syndrome (NS) has been reported previously in different ethnic and racial groups with divergent results. The human PON1 gene contains two coding region polymorphisms leading to two different PON1 isoforms. Objectives: The aim of the present study was to find out the association between the PON1 (Q192R and L55M) polymorphisms and their relation with serum PON1 activity as well as lipid profile tests (total cholesterol, TC; triglycerides, TG; high-density lipoprotein cholesterol, HDL-c; and low-density lipoprotein cholesterol, LDL-c) in children with NS. Methods: This study included a total of 80 participants (40 with NS in the age group of 2-14 years and 40 age and sex-matched healthy controls). The PON1 enzyme activity and lipid profile tests were measured in serum samples of all included participants. The PON1 genotype was determined by PCR-restriction enzyme fragment length polymorphism (PCR-RFLP) for both PON1 alleles (192 and 55) SNPs. Results: Our findings showed that the mean levels of lipid profile tests (TC, TG, LDL-c) were significantly increased in patients when compared with healthy controls (p<0.05), while the HDL-c concentration was significantly decreased in patients than that of controls. Also, the patients had significantly lower concentrations of PON1 when compared with the controls regardless of the genotype Q192R and L55M polymorphisms. Moreover, the homozygous RR genotype for PON1 SNP 192 and MM homozygous genotype for PON1 SNP 55 were significantly frequent in patients when compared with the controls. Conclusions: Our results support that the presence of the homozygous RR genotype for PON1 SNP 192 and MM homozygous genotype for PON1 SNP 55 were significantly higher in patients compared with the controls.