DAM is molecularly identified as immune cells that display the typical microglial markers Iba1, Cst3, and Hexb, as well as the upregulation of “neurodegeneration” genes, including numerous recognized AD risk genes (e.g., Apoe, Lpl, Trem2, and Ctsd), and the downregulation of “homeostatic” gene set (e.g., P2ry12/P2ry13, Cx3cr1, Cst3 and Tmem119) (Hansen et al., 2018; Wang, 2021; Wu and Eisel, 2023). Here, TREM2 is linked to Alzheimer disease.