The interaction between oral and systemic disease has been well demonstrated in the last decades. On the one hand, oral diseases can affect the initiation and progress of various systemic diseases such as cardiovascular, neurological, and respiratory diseases; on the other hand, systemic diseases can increase the susceptibility of suffering from oral diseases. Both oral and systemic diseases share several common risk factors, which contribute to the incidence of both diseases, for example, aging, smoking, alcohol abuse, gender, education and socioeconomic status, and genetic susceptibility. Common genetic risk factors for oral and systemic disease that may predispose certain individuals to suffer from both diseases have been identified by much previous scientific evidence.

Many types of gene families are involved in the shared mechanisms between oral and systemic diseases, for instance, immunosuppression genes, autoimmune genes, inflammatory mediator genes, programmed cell death-related genes or neuropeptide genes. Regarding the immunosuppression genes, organ transplant recipients with a long history of taking immunosuppression drugs have an increased risk of periodontitis, oral mucosal disease especially oral hairy leukoplakia, and oral squamous cell carcinoma; thereby indicating the involvement of immunosuppression genes in the initiation of oral disease. In addition, inflammatory mediator genes such as cytokines and chemokines have been well demonstrated to be the linkage between oral and systemic disease, because of the involvement of an imbalanced inflammatory immune response in both diseases. Particularly, the inflammatory mediators might promote the formation of tumor microenvironment and lead to the initiation and progression of malignant diseases. Although some previous evidence has shown the genetic linkage between oral and systemic diseases, the genetic mechanisms linking oral disease and systemic disease still warrant further and deeper investigations.

Therefore, in this Special Issue, we will collect original and review articles focusing on recent advances in the shared genetic mechanisms between oral disease and systemic disease. Both original research and review articles are welcomed.

Potential topics include but are not limited to the following:

• Bioinformatics research focusing on the shared molecular mechanisms between oral and systemic diseases
• Systematic reviews using meta-analysis to summarize the association between oral and systemic diseases
• Studies using RNA sequencing technology to identify genetic alterations in oral diseased patients with a certain systemic disease
• Potential biomarkers in the interplay between periodontal diseases and diabetes, autoimmune disease, obesity, or cardiovascular diseases
• Mediating effects of programmed cell death in oral and systemic disease and the role in bidirectional autoimmunity
• Potential biomarkers and mechanisms between oral health and lifestyle factors like tobacco consumption or nutrition
• The effects of potential drug agents on periodontal and systemic inflammation
• Genetic and epigenetic biomarkers for the diagnosis and treatment of oral and systemic disease
• Clinical and basic research in the progress of oral and systemic diseases, especially revealing the bidirectional relationship
• Interdisciplinary research in oral and systemic disease