Objectives: Toll-like receptors (TLR) are signal molecules that act as pattern recognition receptors (PRRs) to bacterial cell wall components. Due to this particular reason, differences in host susceptibility to periodontitis are owed mainly to functional polymorphisms located in PRRs. The aim of this study was to investigate relationships between periodontitis and variation in the TLR4 gene: Thr/Ile (rs4986791), Gly/Thr (rs2149356), Asp/Gly (rs4986790).
Subjects and Methods: The study design was case-control performed in sample of Egyptians; 50 periodontitis and 50 with healthy periodontium . Clinical periodontal parameters were recorded and blood samples were taken for all participants. For genetic analysis Real time polymerase chain reaction was the method for recording different genotypes related to single nucleotide polymorphisms in TLR4 gene.
Results: The group of periodontitis had a significantly higher frequency of TT (mutant) genotype (30%), when compared to 8 % in the control group. Conversely, the control group showed a higher frequency of GT (heterozygous) genotype (62%), in comparison to 44% in periodontitis group. It was calculated that the relative risk of periodontal infection in patients with GT genotype is 0.935. The relative risk of periodontal infection in patients with TT genotype is 2.544.
Conclusion: In our sample of the Egyptian population, TLR4 SNP rs2149356 was linked with periodontitis. Subjects with homozygous mutant genotype (TT) were more susceptible to periodontitis. While subjects with heterozygous genotype (GT) are at a less risk than homozygous compared to heterozygous genotype (GG). TLR4 SNPs Asp/Gly rs4986790 and Thr/Ile rs4986791 do not exist in the population.