CD200 and Alzheimer disease: In this study, intersection analysis of diseases and Cytoscape topology revealed that PTGS2, GZMA, PLAUR, CD200, GZMH, and MMP19 were bridges between AD and POP, and the molecular functions of these genes are predominantly enriched in serine-type endopeptidase activity, serine-type peptidase activity, and serine hydrolase activity, which may be linked to the metabolism of substances in vivo.