TREM2 and Alzheimer disease: We have shown that loss‐of‐function of TREM2 impairs the phagocytic activity of microglial cells and reduces clearance of amyloid β‐peptide (Aβ; Kleinberger et al, 2014), suggesting that TREM2 may play an important role in the development of AD pathology and neurodegeneration during the course of the disease.