MAPT and early-onset autosomal dominant Alzheimer disease: As a microtubule-associated protein, tau plays a vital role in the pathogenesis of a series of neurodegenerative diseases, including Alzheimer's disease (AD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), Pick’s disease (PiD), and frontotemporal dementia with Parkinson's disease-17 (FTDP-17) [51].