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-4Rα 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.