Are There Any Common Genetic Risk Markers for Rheumatoid Arthritis and Periodontal Diseases? A Case-Control Study.

BACKGROUND

Several studies suggest that there is a biologically plausible connection between rheumatoid arthritis (RA) and periodontal diseases (PD). Both disorders are characterized as multifactorial diseases potentially sharing common risk factors. Based on the inflammatory nature of RA and PD, the impact of genetic variations of genes of the immune system on both diseases was studied in this study.

MATERIALS AND METHODS

We conducted a case-control study ( = 201) comparing 101 RA patients suffering from periodontal disease of different severities (no/mild PD vs. severe PD) with 100 systemically healthy controls without RA and severe PD. The genotype, allele, and haplotype distributions of 22 SNPs of 13 pro- and anti-inflammatory cytokines were assessed applying sequence-specific PCR.

RESULTS

Evaluating the impact of cytokine SNPs in RA, we identified the G allele of rs1801275 in IL4R ( = 0.043) and the G allele of rs361525 in TNF ( = 0.005) as disease-associated risk factors in bivariate analyses. In multivariate analyses, these significant associations could not be proven. The A allele of rs2430561 in IFN was indicative for severe periodontitis among the patients with rheumatoid arthritis ( = 0.039). Investigating the impact of rs2430561 in IFN on comorbidity using binary logistic regression analyses, the A allele was confirmed as an independent risk factor for severe periodontal disease and RA ( = 0.024).

CONCLUSIONS

These results emphasize the association of genetic variations in proinflammatory cytokines (TNF and IFN) and cytokine receptor (IL4R) and RA and periodontal diseases. In multivariate analyses, the A allele of IFN was proven to be a significant marker of RA and PD comorbidities. The study broadens the knowledge about disease-specific differences in genetic composition and provides an improved understanding of a possible association of both diseases.