Association of single nucleotide gene polymorphism at interleukin-1beta +3954, -511, and -31 in chronic periodontitis and aggressive periodontitis in Dravidian ethnicity.

Background: Interleukin (IL)-1beta gene polymorphisms are considered a potential risk factor for periodontal disease. The aim of this study is to identify the association of IL-1beta gene polymorphisms with chronic periodontitis and aggressive periodontitis in a Malayalam-speaking Dravidian population from South India.

Methods: The case-control study consisted of 43 patients with chronic periodontitis and 54 patients with aggressive periodontitis as cases, and the control group consisted of 101 healthy subjects. All subjects were genotyped for IL-1beta +3954, -511, and -31 loci by polymerase chain reaction amplification followed by restriction enzyme digestion and gel electrophoresis. Genotype, allele, and haplotype analyses were done.

Results: Analyses for allele and genotypes showed a high frequency of the C allele and CC genotype for single nucleotide polymorphism IL-1beta +3954 in the group with chronic periodontitis and no difference for patients with aggressive periodontitis compared to controls (P <0.05). Haplotype analysis showed that IL-1beta -31 and -511 were in strong linkage disequilibrium in all groups. The IL-1beta -31 allele T was in linkage with allele T of IL-1beta +3954 in the control group.

Conclusions: In the Malayalam-speaking Dravidian population, allele C of IL-1beta +3954 appeared to be an important risk factor for chronic periodontitis. The IL-1beta -31 allele T was in linkage with allele T of IL-1beta +3954 in the control group. No gene polymorphisms were found in patients with aggressive periodontitis. More studies with a larger sample size involving the entire cluster of the IL-1beta gene are necessary to determine the exact role of IL-1beta gene polymorphisms in periodontal disease.