Polymorphisms of interleukin-4--related genes in Japanese children with minimal change nephrotic syndrome.

BACKGROUND: Minimal change nephrotic syndrome (MCNS) in children frequently is associated with allergy and immunoglobulin E production. T Helper subtype 2 cytokines, such as interleukin-4 (IL-4), may have an important role in the development of atopy. We investigated the associations of gene polymorphisms of IL-4, its receptor (IL-4R), and the signal transducer and activator 6 (STAT6) gene with MCNS.

METHODS: We analyzed these polymorphisms in Japanese children with MCNS (n = 58) and healthy controls with neither allergic nor renal disease (n = 63). The polymerase chain reaction (PCR) and restriction fragment length polymorphism method was used for the IL-4 promoter gene polymorphism (-590C/T), and PCR single-strand conformation polymorphism analysis was used for the IL-4Ralpha chain gene (1902A/G) and STAT6 3' untranslated region (2964G/A) polymorphisms.

RESULTS: There was a significant difference between the MCNS group and controls in genotypic distribution of IL-4 promoter gene polymorphism. Frequency of the T allele was significantly lower in the MCNS group than controls. There was no difference between the MCNS group and controls in the IL-4R gene polymorphism. In the STAT6 gene, no significant differences in genotypic and allelic distribution were observed between the 2 groups. However, there were significant differences between patients who did not need cytotoxic agents or who experienced 3 or fewer relapses and controls.

CONCLUSION: These results suggest that genetic variations in the IL-4 and STAT6 genes may be associated with predisposition to MCNS, partially the clinical course of MCNS.