Differences in Inflammatory Genetic Profiles in Periodontitis Associated with Genetic and Immunological Disorders: A Systematic Review

Background: Periodontitis is a multifactorial inflammatory disease influenced by immune and genetic factors. Certain genetic and immunological disorders, such as Down syndrome (DS), Leukocyte Adhesion Deficiency type I (LAD-I), and Papillon–Lefèvre syndrome (PLS), are associated with early-onset and severe periodontitis. Understanding their molecular and immunological mechanisms is crucial for advancing personalized therapeutic approaches. Methods: A systematic review was conducted following PRISMA 2020 guidelines to compare inflammatory gene expression profiles in patients with periodontitis associated with genetic or immune-mediated disorders and those without systemic conditions. Searches were performed in PubMed, Scopus, Web of Science, and Embase for studies published between 2010 and June 2025. Eligible studies reporting cytokine profiles or inflammatory gene expression were included and analyzed. Results: Six case–control studies met the inclusion criteria: three on DS, two on LAD-I, and one on PLS. DS patients showed increased serum levels of IL-1 beta, TNF-alpha, IL-4, IL-10, and IFN-gamma, with dysregulation of STAT1, STAT3, and SOCS3. LAD-I was characterized by overexpression of IL-17A, IL-6, IL-23, G-CSF, CXCL2, and CXCL5, indicating IL-17–driven inflammation and excessive neutrophil activation. In PLS, cathepsin C deficiency impaired activation of the antimicrobial peptide LL-37, leading to compromised host defense and accelerated tissue breakdown. Conclusions: Patients with periodontitis linked to genetic or immune-mediated disorders exhibit distinct inflammatory gene expression signatures that enhance disease susceptibility and progression. Identifying these immunoinflammatory pathways may guide precision periodontal therapies, although larger, standardized studies are required to validate these findings.