Interleukin-1 receptor gene variants are associated with aggressive periodontitis in the Japanese

Objective: Previous studies have indicated that type-1 and type-2 interleukin-1 (IL-1) receptors (IL-1R1 and IL-1R2) play important roles in periodontitis progression. We investigated the association between periodontitis and polymorphisms in the IL-1R1 and IL-1R2 genes (IL1R1 and IL1R2). Design: We searched for genetic variants in IL1R1 and IL1R2 in 24 Japanese patients with aggressive periodontitis (AgP) and 24 periodontally healthy controls. Thirty-eight single nucleotide polymorphisms (SNPs) were identified within genomic regions containing all exons and relevant exon-intron boundaries in IL1R1 and IL1R2. Possible associations of each gene locus with AgP were investigated in 119 AgP patients and 102 periodontally healthy controls using allelotypes, genotypes, and haplotypes. Results: Significant differences were noted in the frequencies of 3 SNPs in IL1R2 (rs3819370, rs3218974 and rs3218977) for AgPs and controls (p = 0.012, p = 0.008, and p = 0.038, respectively), after adjustment for gender and smoking status in the additive model (p = 0.016, p = 0.007, and p = 0.027, respectively) and 2 haplotypes (p = 0.010 and p = 0.011, respectively) constructed from 2 SNPs (rs3819370 and rs3218974) that showed the lowest p-values after adjustment of covariates in additive models. Conclusion: A genetic susceptibility locus for AgP may lie within or close to the IL1R2 locus. Further studies in other populations are necessary to confirm these results. (C) 2014 Elsevier Ltd. All rights reserved.