Associations between IL-1RN variable number of tandem repeat, IL-1β (-511) and IL-1β (+3954) gene polymorphisms and urolithiasis in Uighur children of China

Abstract

Objective: Interleukin-1 (IL-1) is a pro-inflammatory cytokine which may be related to urolithiasis. Genetic polymorphisms of the interleukin-1beta (IL-1β) have been proposed as markers for urolithiasis in some areas. Due to the high incidence of urolithiasis in Uighur children (Xinjiang, China) and existence of ethnic difference, our aim is to explore the potential of IL-1 gene polymorphisms and urolithiasis among these children.

Methods: Genomic DNA extracted from peripheral blood of 115 patients and 98 controls were used for genotype polymorphisms analyses. IL-1 receptor antagonist (IL- 1RN) gene variable number of tandem repeat (VNTR) gene polymorphisms were analyzed by PCR method. PCR-based restriction analysis was done for the IL-1β (-511) and IL-1β (+3954) gene polymorphisms by endonucleases Ava I and Taq I, respectively. The genotype distribution, allele frequencies, carriage rate, and haplotype frequencies were statistically analyzed.

Results: No significant differences were observed in genotypic frequencies between pediatric urolithiasis patients and control group for IL-1RN gene (χ ²=1.906, p=0.605), IL-1β (-511) gene (χ ²=0.105, p=0.949), or IL-1β (+3954) gene (χ ²=3.635, p=0.169). There were yet no significant differences of the allele frequencies of IL-1RN VNTR gene (p=0.779), IL-1β (-511) gene (p=0.941), and IL-1β (+3954) gene (p=0.418) in the case and control groups, as well as the carriage rate and haplotype of them (all p>0.05).

Conclusions: The associations between IL-1RN VNTR, IL-1β (-511) and IL-1β (+3954) genes polymorphisms and urolithiasis were not significant in Uighur children. The results need to be confirmed in studies with larger population sample size, as well as in other ethnic groups.

Keywords: IL-1RN variable number of tandem repeat gene; IL-1β (+3954) gene; IL-1β (−511) gene; Single nucleotide polymorphisms; Uighur children; Urolithiasis.

Figure 1

The results of agarose gel electrophoresis. (A) IL-1RN VNTR gene; (B) IL-1β (−511) gene; (C) IL-1β (+3954) gene. I/I, IL-1RN VNTR gene wild type; II/IV, I/III, I/IV and I/II, IL-1RN VNTR gene heterozygote; II/II, IL-1RN VNTR gene mutant type; T/C, IL-1β (−511) gene heterozygote; C/C, IL-1β (−511) gene wild type; T/T, IL-1β (−511) gene mutant type; E₁/E₂, IL-1β (+3954) gene heterozygote; E₁/E₁, IL-1β (+3954) gene wild type; E₂/E₂, IL-1β (+3954) gene mutant type; IL-1β, interleukin-1beta; VNTR, variable number of tandem repeat.