Aim: Toll-like receptors (TLRs) belong to the pattern recognition receptors family of signal molecules that recognize conserved microbial structures. The aim of this study was to analyse polymorphisms in the TLR genes and their association with chronic periodontitis (CP).
Material and methods: Two polymorphisms (2408G/A, i.e. Arg753Gln and -16934A/T) in TLR-2 and three variants (-1486C/T, -1237C/T and+2848A/G) in the TLR-9 genes were studied in 222 patients with CP and 259 unrelated controls. All polymorphisms were detected using the polymerase chain reaction-restriction fragment length polymorphism methods. Subgingival bacterial colonization was investigated by the VariOr Dento test.
Results: No significant differences were found in allele and genotype frequencies of all polymorphisms between patients and controls. Nevertheless, complex analysis revealed differences in TLR9 haplotype frequencies between both groups (p=0.001). Specifically, the haplotype T(-1486)/T(-1237)/A(2848) was significantly more frequent (9.6%versus 2.8%, p<0.000001) and the haplotype T(-1486)/T(-1237)/G (2848) of the TLR9 gene was less frequent (35.9%versus 43.3%, p=0.01) in patients than in controls. However, no significant relationships between periodontal pathogens, TLR polymorphisms and CP were found.
Conclusions: In conclusion, although no significant role of the TLR2 gene in periodontitis was found, our results indicate that TLR9 haplotypes may be associated with susceptibility to CP.