MAPT and Alzheimer disease: The amyloid cascade hypothesis, now integrated in the National Institute on Aging–Alzheimer’s Association amyloid/tau/neurodegeneration framework (NIA-AA ATN) biomarker framework, which uses biomarkers of Aβ (A), tau (T), and neurodegeneration (N) to define AD, drives the development of disease-modifying monoclonal antibodies that target upstream Aβ pathology in AD.