Association of interleukin-18 gene polymorphisms with calcium oxalate kidney stone disease

Objective. The interleukin-18 (IL-18) encoding gene has three common single-nucleotide polymorphisms at 607C/A, 137G/C and 105A/C, which have been reported to be associated with several diseases. The aim of this study is to test whether IL-18 polymorphisms could act as genetic markers for renal stone disease. Material and methods. A control group of 104 healthy subjects, and 272 patients with recurrent calcium oxalate stones were examined. Polymerase chain reaction-based restriction endonuclease analysis was used to detect IL-18 polymorphisms. Results. The patient and control groups differed significantly in genotypic expression of the IL-18 105A/C polymorphism. The prevalence of the A/C C/C genotypes in the patients was higher than that in the controls. The allelic frequency of IL-18 105A/C differed significantly between the patients and the controls. The odds ratio (OR) of the A/C heterozygote of IL-18 105A/C associated with urolithiasis was 2.772. The OR of the A/C C/C genotypes of IL-18 105A/C associated with urolithiasis was 3.097. The OR per copy of the C allele of IL-18 105A/C associated with urolithiasis was 4.143. There were also significant differences in the prevalence of genotype IL-18 137G/C polymorphisms between the patients and controls. The distribution of the G/G homozygote in the patients was higher than that in the controls. There was no significant difference in genotype and allelic frequency at the IL-18 607C/A polymorphism between patients and control subjects. Conclusion. The results indicate that IL-18 105A/C polymorphisms may play a role in the development of urolithiasis.