TREM2 and Alzheimer disease: Conditional genetic manipulation and genome-wide association studies have identified several immune-related genes (TREM2 [123], CX3CR1, CR1 [124], CD33 [125], ATP-binding cassette transporter (ABCA) 7 [126], and BIN1 [127]) as risk factors for tau pathology and AD, thereby supporting the critical involvement of glial cells and neuroinflammation in tauopathies.