Toll-like receptor 2 and 4 gene polymorphisms in generalized aggressive periodontitis

Toll-like receptors (TLRs) recognize exogenous ligands such as lipopolysaccharide and bacterial lipoprotein during the immune responses to pathogens. The aim of the present study was to investigate whether TLR2 and TLR4 gene polymorphisms are related to susceptibility to generalized aggressive periodontitis (GAgP).

A total of 245 subjects were included in the present study. Genomic DNA was obtained from the peripheral blood of 90 patients with GAgP and 155 periodontally healthy subjects. Probing depth, clinical attachment loss, plaque accumulation, and bleeding on probing were recorded. The TLR2 gene Arg753Gln and Arg677Trp polymorphisms and TLR4 gene Asp299Gly and Thr399Ile polymorphisms were genotyped by the polymerase chain reaction-restriction fragment length polymorphism method. The data were analyzed by chi2 and Mann-Whitney U tests and logistic regression analysis.

There was no significant difference in the distribution of TLR2 and TLR4 genotypes and allele frequencies between GAgP patients and healthy subjects (P > 0.05). The TLR2 753Gln allele was found in 3.9% of the GAgP patients compared to 6.1% in the healthy group. The GAgP patients and healthy subjects did not show homozygosity for the TLR2 mutant alleles. The TLR2 677Trp mutant allele was not found in any of the subjects; 2.2% of the GAgP patients and 2.9% of the periodontally healthy subjects were identified as having the TLR4 299Gly polymorphic allele. With regard to the TLR4 399Ile polymorphic allele, 1.1% of the GAgP patients and 2.3% of the periodontally healthy subjects had this allele.

The present study failed to find any significant association between the TLR polymorphisms and GAgP, potentially because of the small sample size. To the best of our knowledge, this was the first study to examine the prevalence of these polymorphisms in a Turkish population with aggressive periodontitis.