DAM is identified molecularly as immune cells that display the typical microglial markers Iba1, Cst3, and Hexb, together with the upregulation of “neurodegeneration” genes, including numerous recognized AD risk genes (e.g., Apoe, Lpl, Trem2, Tyrobp, and Ctsd), and the downregulation of “homeostatic” gene set (e.g., P2ry12/P2ry13, Cx3cr1, Cst3, Cd33, Csf1r, and Tmem119) [51–53]. Here, CX3CR1 is linked to Alzheimer disease.