Recent single-cell transcriptomic analysis from Alzheimer’s disease mice brains has shed some light on the transcriptional signature of plaque-associated microglia (named ‘disease-associated microglia’, DAM), in which there is a two-step switch from a homeostatic (Tmem119, P2ry12, Cx3cr1 signature) to a pathology-associated phenotype (Apoe, Trem2, Csf1, Itgax signature), with TREM2 as a major phenotypic modulator (Keren-Shaul et al., 2017). Here, TREM2 is linked to Alzheimer disease.