MMP9 and periodontitis: ORA and GSEA analysis observed changes in neutrophil-mediated immunity, response to bacterium, humoral immune response, IL-17 pathway, and TNF-α pathway, of which are related to immune response and inflammatory response; DO analysis also identified potential target genes including MMP9, VEGFA, IL10, IL1A, IL1B, IL2RA, and IL6, which may be related to periodontal destruction, vascular complication, and skin disease of pEDS; In addition, STRING network analysis showed the relationship between genes involved in the classical complement activation pathway and the DEGs related to periodontitis.