TREM2 and Alzheimer disease: On the contrary, other studies revealed that TREM‐2 deficiency, by limiting microglia activation and phagocytosis, facilitates Aβ plaque buildup, and injury of adjacent neurons in mouse model of AD (Jay, von Saucken, & Landreth, 2017; Ulrich et al., 2014; Y. Wang et al., 2015; Y. Wang et al., 2016; Yuan et al., 2016) and results in impaired elimination of supernumerary synapses during brain development (Filipello et al., 2018).