Elevated cytokine levels of IL-6 and TNF in saliva have been shown to be correlated with oral mucosal changes in CD patients and to be equally elevated in periodontitis patients, so it is believed that there are correlations between mucosal changes and the severity and degree of periodontitis based on this evidence, which could also be due to common genetic background between these two entities (4, 18–20). The gene discussed is TNF; the disease is periodontitis.