Association of vitamin D receptor gene polymorphisms with chronic and aggressive periodontitis in Jordanian patients.

Vitamin D acts through binding with vitamin D receptor (VDR) and is responsible for regulating bone metabolism and mineralization; it also suppresses the immune system. The aim of this study was to investigate if VDR gene polymorphisms are associated with chronic periodontitis (CP) and aggressive periodontitis (AgP) in a Jordanian population. A total of 99 patients with CP, 63 patients with AgP, and 126 controls were genotyped using PCR-restriction fragment length polymorphism (RFLP) for BsmI, ApaI, and TaqI single nucleotide polymorphisms (SNPs). The association was determined after correcting for confounding factors using multivariate logistic regression analysis. Estimation of haplotype frequencies was carried out using the EH program, and haplotypes were constructed using the phase 2.1 program. After correcting for confounding factors, multivariate logistic regression analysis revealed that inheritance of the BsmI bb genotype or the ApaI aa genotype was associated with increased risk of developing CP (OR = 2.4 and OR = 3.4, respectively) but with reduced risk of developing AgP (OR = 0.4 and OR = 0.3, respectively). This was further supported by association of the ba haplotype with CP but not with AgP. This study supports an association of VDR gene polymorphisms with CP and AgP in a Jordanian population; however, the pattern of association was different between the two diseases.

Investigation of the interleukin-1 gene cluster polymorphisms in Jordanian patients with chronic and aggressive periodontitis.

OBJECTIVE: Interleukin-1 (IL-1) is a proinflammatory cytokine that is highly elevated in response to bacterial biofilms and is a potential risk factor for periodontal diseases. IL-1 gene polymorphisms have been associated with the IL-1 level. The aim of this study was to investigate if IL-1 gene cluster polymorphisms are associated with chronic (CP) and aggressive (AgP) periodontitis in a Jordanian population. METHODS: A total of 100 CP, 80 AgP patients and 80 controls were genotyped using PCR for IL-1RN-86-bp VNTR and PCR-RFLP for IL-1A-889, IL-1B-511, -35, +3953, and IL-1RN +8006, +9589, +11100 SNPs. The distribution of alleles and genotypes between groups was compared using χ(2) analysis. Estimation of haplotype frequencies was carried out using the EH programme. RESULTS: The IL-1RN8006 SNP and the IL-1RN-VNTR were associated with CP but not with AgP. The C allele and TC genotype of IL-1RN8006 were increased in CP (P(corr)=0.002, 0.00026 respectively). The A1 allele and A1/A1 genotype of the IL1-RN-VNTR were significantly increased in CP (P(corr)=0.0007, <0.0001 respectively). The CA1 haplotype formed by both markers was present in 29 CP patients but not in any of the controls (P<0.0001). No significant differences were found in the distribution of allele and genotype frequencies of the other markers between CP and AgP cases and controls. CONCLUSIONS: IL-1RN 8006 and IL-1RN VNTR were associated with CP but not AgP in a Jordanian population, whilst other investigated markers in IL-1A, IL-1B and IL-1RN were not associated with either CP or AgP.