MAPT and Alzheimer disease: The central role of tau aggregation is shared across a spectrum of disorders termed tauopathies, which include AD, progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick's disease, chronic traumatic encephalopathy (CTE), and frontotemporal dementia with Parkinsonism linked to chromosome 17 (FTDP-17) (2, 15).