Toll-like receptor-4 Single Gene Polymorphism and Chronic Periodontitis Susceptibility in a Sample of Egyptian Population: A Case-Control Study

Abstract

Periodontitis is a multifactorial disease influenced partly by genetics. Activation of pattern recognition receptors (PRRs) can lead to the up-regulation of inflammatory pathways, resulting in periodontal tissue destruction. Hence, functional polymorphisms located in PRRs can explain differences in host susceptibility to periodontitis. Toll-like receptors are signal molecules essential for the cellular response to bacterial cell wall components. Genetic variations of host’s immune-related DNA molecules such as gene polymorphisms affect the occurrence and the patterns of diseases. Gene polymorphisms including single nucleotide polymorphisms (SNPs) that cause allelic variations in genes encoding host defense, could affect the susceptibility and progression of periodontal disease. Thus, there is a great significance to discuss the gene variants of immune-related molecules such as TLR4 for the prevention and treatment of periodontitis. The aim of this study was to investigate relationships between periodontitis and variations in the TLR4 gene such as TLR-4 Gly/Thr (rs2149356), Asp/Gly (rs4986790) and Thr/Ile (rs4986791). Genomic DNA was obtained from peripheral blood of 50 patients with periodontitis and 50 periodontally healthy subjects. TLR4 SNPs were genotyped by a PCR and the data were analysed by a x2-test and by relative risk estimation. The variants of rs4986790 and rs4986791 were not found in 100 Egyptian subjects. Rs2148356 was found to be associated with periodontitis susceptibility. The allele frequency was also measured to further ensure the association of the mutant allele to periodontitis. The allele with the higher frequency in the periodontitis group is T which is the mutant allele, while for the control group, it is the G allele which is the normal allele at a statistically significant value (p=0.064).