β-defensin-1 SNPs in Japanese periodontitis

Background and Objective: Periodontitis is a multifactorial disease associated with genetic and environmental factors. Recent reports have shown that single-nucleotide polymorphisms (SNPs) are associated with susceptibility to common diseases such as not only diabetes and hypertension but also periodontitis. Although the oral cavity is continuously exposed to various pathogenic organisms, the oral conditions are well controlled by innate and acquired immune systems. Antimicrobial peptides (AMPs) play an important role in the innate immune system; however, the association of AMP-SNPs with periodontitis has not been fully elucidated. The aim of the present study was to investigate the relationship between AMP-SNPs and periodontitis in Japanese. Methods: One hundred and five Japanese subjects were recruited, which included 21 patients with aggressive, 28 with severe, 13 with moderate and 22 with mild periodontitis, as well as 21 age-matched healthy controls. Genomic DNA was isolated from peripheral blood in each subject. Genotypes of four reported SNPs of β-defensin-1 and lactoferrin genes (DEFB1: rs1799946, rs1800972 and rs11362; and LTF: rs1126478) were investigated using the PCR-Invader assay. Protein levels of AMP in gingival crevicular fluid (GCF) were quantified by ELISA. Results: Case-control studies revealed that the -44 CC genotype of DEFB1 (rs1800972) was associated with severe chronic periodontitis (odds ratio 4.15) and with combined severe and moderate chronic periodontitis (odds ratio 4.04). No statistical differences were found in other genotypes. The β-defensin-1 concentrations in GCF were significantly lower in the subjects with the -44 CC genotype of DEFB1 than in those without this genotype. No significant differences between GCF concentrations of AMPs and other genotypes were detected. Conclusion: The -44 CC genotype of the β-defensin-1 gene (DEFB1 rs1800972) may be associated with susceptibility to chronic periodontitis in Japanese