TREM2 and Alzheimer disease: In this sense, several mutations in TREM2 (such as R47H TREM2) produce an increased risk for late-onset AD (Yeh et al., 2016) and impair the microglial signals involved in survival, proliferation, chemotaxis, and phagocytosis (Jay et al., 2017; Ulrich et al., 2017; Yeh et al., 2017).