TREM2 and Alzheimer disease: Additional evidence for the signaling capacity of full‐length TREM2 comes from the analysis of the AD‐associated p.TREM2 H157Y variant (Jiang et al, 2016) which increases shedding of TREM2 and concomitantly reduces TREM2‐dependent phagocytosis (Schlepckow et al, 2017), thus furthermore indicating that the amount of cell‐surface TREM2 correlates with microglial activity.