Mice with defective TREM2 signaling display impaired microglial response to injury and amyloid plaque pathology (Kleinberger et al., 2017; Ulland et al., 2017; Wang et al., 2015), a phenotype also demonstrated in human AD brain tissue (Toomey et al., 2020; Ulrich et al., 2014; Wang et al., 2016) (for a recent review on TREM2, please refer to: Deczkowska, Weiner, & Amit, 2020). The gene discussed is TREM2; the disease is Alzheimer disease.