Single-cell RNA-seq of amyloidosis mouse models revealed that a microglial subpopulation transitions from a homeostatic state to an activated state termed ‘disease-associated microglia’ or ‘activated response microglia’4,55, with increased expression of microglial activation genes (including APOE, AXL, TREM2 and CD74)53–56 that are crucial regulators of phagocytic processes81–84. This evidence concerns the gene TREM2 and amyloidosis.