Single nucleotide polymorphisms of pattern recognition receptors and chronic periodontitis.
OBJECTIVE
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. This study investigated single nucleotide polymorphisms of PRRs including toll-like receptor (TLR)2 (G2408A), TLR4 (A896G), TLR9 (T1486C), TLR9 (T1237C) and CD14 (C260T) in patients with chronic periodontitis and in periodontally healthy subjects.


METHODS
One-hundred and fourteen patients with chronic periodontitis and 77 periodontally healthy subjects were genotyped using TaqMan® allelic discrimination assays. Fisher's exact test and chi-square analyses were performed to compare genotype and allele frequencies.


RESULTS
The frequency of subjects with the CC genotype of CD14 (C260T) (24.6% in the chronic periodontitis group vs. 13% in the periodontally healthy group) and those expressing the T allele of CD14 (C260T) (CT and TT) (75.4% in the chronic periodontitis group vs. 87% in the periodontally healthy group) was statistically different among groups (p = 0.04). Homozygocity for the C allele of the CD14 (C260T) polymorphism (CC) was associated with a two--fold increased susceptibility to periodontitis (p = 0.04; odds ratio, 2.49; 95% confidence interval, 1.06-6.26). Individuals with the CC genotype of TLR9 (T1486C) (14.9% in the chronic periodontitis group vs. 28.6% in the periodontally healthy group) and those expressing the T allele of TLR9 (T1486C) (CT and TT) (85.1% in the chronic periodontitis group vs. 71.4% in the periodontally healthy group) were also significantly differently distributed between groups without adjustment (p = 0.03). Further analysis of nonsmokers revealed a significant difference in the distribution of genotypes between groups for TLR9 (T1486C; p = 0.017) and CD14 (C260T; p = 0.03), polymorphisms again without adjustment.


CONCLUSIONS
The CC genotype of CD14 (C260T) is related to susceptibility to chronic periodontitis in Caucasians. In addition, differences observed in the distribution of TLR9 (T1486C) genotypes between groups warrant further investigation.
Virginia Commonwealth University, School of Dentistry, Department of Periodontics, Richmond, VA 23298-0566, USA. ssahingur@vcu.edu
S E
SE
Sahingur
X-J
XJ
Xia
J
J
Gunsolley
H A
HA
Schenkein
R J
RJ
Genco
E
E
De Nardin
D000225:Adenine; D055113:Chronic Periodontitis / Q000235:genetics*; D003596:Cytosine; D003774:Dental Plaque Index; D005260:Female; D005787:Gene Frequency / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000235:genetics; D005838:Genotype; D006147:Guanine; D006720:Homozygote; D006801:Humans; D018950:Lipopolysaccharide Receptors / Q000235:genetics*; D008297:Male; D008875:Middle Aged; D017622:Periodontal Attachment Loss / Q000235:genetics; D010512:Periodontal Index; D010514:Periodontal Pocket / Q000235:genetics; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D012907:Smoking; D013941:Thymine; D051195:Toll-Like Receptor 2 / Q000235:genetics; D051197:Toll-Like Receptor 4 / Q000235:genetics; D051217:Toll-Like Receptor 9 / Q000235:genetics; D051193:Toll-Like Receptors / Q000235:genetics*
D018950:Lipopolysaccharide Receptors; C495342:TLR2 protein, human; C495345:TLR4 protein, human; C495371:TLR9 protein, human; D051195:Toll-Like Receptor 2; D051197:Toll-Like Receptor 4; D051217:Toll-Like Receptor 9; D051193:Toll-Like Receptors; D006147:Guanine; D003596:Cytosine; D000225:Adenine; D013941:Thymine