In the realm of neurodegenerative diseases, the upregulation of APOE4 in microglia leads to a decline in ApoE production, suppression of the APOE-trem2-plcg2 signaling pathway, augmentation of TNF-α concentrations, and acceleration of inflammatory conditions and lipid metabolism dysfunctions [78, 128]. The gene discussed is APOE; the disease is neurodegenerative disease.