Association of Interleukin-1B Gene Polymorphisms and Haplotype Structure with Peridontitis

Objectives: IL-1B gene polymorphisms are reportedly related to the onset and severity of periodontitis. Recent studies suggest that analysis of IL-1B gene haplotypes can provide an understanding of of IL-1B gene regulation and its clinical relevance. This case-control study investigated associations of IL-1B gene polymorphisms and haplotypes with generalized aggressive (GAP) and generalized chronic periodontitis (GCP) in a Turkish population.

Methods: Fifty-two GAP, 53 GCP patients and 42 HC individuals were genotyped for IL-1B T-31C, C-511T and C+3954T single nucleotide polymorphisms (SNPs) by polymerase chain reaction followed by restriction enzyme digestion and gel electrophoresis. The allele frequencies and allele association in GAP, GCP and healthy control (HC) groups were analyzed using Chi-Square tests. An Expectation-Maximization algorithm was used to estimate haplotype frequencies.

Results: In the GAP and GCP groups, there was no significant difference in the allele frequencies for the three SNPs from that observed in the HC group. The -31T>C and -511C>T SNPs exhibited a significant association with GAP cases (P=0.024 and P=0.017, respectively), but there was no apparent association between +3954C>T and GAP.

None of these SNPs exhibited a significant association with GCP. The four most common haplotypes found in all groups were -31C/-511T/+3954C, -31T/-511C/+3954C, -31T/,-511C/+3954T and -31C/-511T/+3954T. The most common haplotype in the GCP group and the control group was -31T/-511C/+3954C, while the most common haplotype in the GAP group was -31C/-511T/+3954C. In both GAP and GCP groups, no haplotypes had significantly different frequency from the control group.

Conclusion: The IL-1B -31 and -511 SNPs could contribute to the risk of developing GAP, but +3954 does not appear to be associated with an increased risk of developing periodontitis. None of detected haplotypes was significantly associated with periodontitis risk, even though haplotypes with -31C and -511T exhibited higher frequencies in the GAP group.

NIH Grant #DE17178