Association of the IL-1RN2 allele with periodontal diseases

ObjectivesInterleukin-1 receptor antagonist (IL-1Ra) gene (IL-1RN) polymorphism is associated with disease susceptibility and activity in several inflammatory diseases. The aim of this study was to investigate IL-1RN genotype and its associations with different periodontal diseases in a group of Turkish subjects.Design and methodsA total of 293 subjects were included in this study. Genomic DNA was obtained from the peripheral blood of 52 patients with generalized aggressive periodontitis (G-AgP), 51 with chronic periodontitis (CP) and 190 reference subjects. A variable number tandem repeat (VNTR) polymorphism in the second intron of the IL-1RN gene was detected by PCR-based methods. Probing pocket depth, clinical attachment loss, plaque accumulation and bleeding on probing (BOP) were recorded. The data were analyzed by the χ2 test, logistic regression and Mann–Whitney U test.ResultsThere were significant differences among the groups in the distribution of IL-1RN genotypes (P = 0.0001) and allele frequencies (P = 0.0001). The frequency of IL-1RN2 allele 2 positivity was higher in the AgP and CP group than the reference group [odds ratio (OR) 6.654, 95% CI: 3.023–16.648; OR 10.327, 95% CI: 4.758–22.412, respectively]. The percentage of sites with BOP was significantly higher in IL-1RN2+ compared to IL-1RN2− CP patients (P = 0.022).ConclusionThese results suggest that IL-1RN2 allele positivity is associated with periodontal disease in a Turkish population.