MAPT and Alzheimer disease: There are 26 tauopathies identified, including Alzheimer’s disease (AD), frontotemporal dementia with parkinsonism-17 (FTDP-17), corticobasal degeneration (CBD), progressive supranuclear palsy (PSP), argyrophilic grain disease (AGD), Pick’s disease (PiD), and other diseases where tau plays a major role.