A dramatic difference in the frequencies of the Lys/Arg single nucleotide polymorphism in the lactoferrin genotype between a small population of patients with localized juvenile periodontitis and healthy subjects has been reported. As the single nucleotide polymorphism could be associated with ethnicity, the present study aimed to investigate the association between polymorphisms of the lactoferrin gene and periodontitis.
Sixty-five patients with aggressive periodontitis, 278 with chronic periodontitis and 88 healthy controls were genotyped for the Lys/Arg polymorphism of the lactoferrin gene at position 29 [reference sequence (rs) 1126478] in the N-terminal alpha-helical region.
The frequencies of the GG genotype and the G allele were highest in the aggressive periodontitis group, followed by the chronic periodontitis group and then the healthy controls. The frequency of the G allele was significantly higher in aggressive periodontitis and chronic periodontitis groups than in healthy controls (p = 0.0037 and 0.0212). Although the difference of the GG genotype distribution between subjects with chronic periodontitis and healthy controls did not reach significance, the distribution of genotypes between aggressive periodontitis and healthy controls was significantly different. The association of the gene polymorphism and aggressive periodontitis still existed, even after adjusting for age, gender and smoking status by logistic regression analysis (GG/AG+AA: odds ratio = 2.16, 95% confidence interval = 1.09-4.35, p = 0.0287). After the study, subjects were further stratified by their smoking status; the GG genotype was still significantly associated with the risk of aggressive periodontitis in the nonsmoking group (odds ratio = 2.69, p = 0.018). However, there were no statistical differences between chronic periodontitis vs. healthy controls and aggressive periodontitis vs. healthy controls in the smoking group.
The present study revealed that the A/G polymorphism in the lactoferrin gene might be associated with aggressive periodontitis. The A allele might reduce the risk of development of aggressive periodontitis in a Taiwanese population. Our results also support the hypothesis that lactoferrin genetic polymorphisms could play a role in the risk for periodontitis separate from the smoking factor. The functionality of this gene's polymorphisms has to be further elucidated.