Tau protein has a pivotal role in the pathology of different diseases: Alzheimer’s disease (AD), chronic traumatic encephalopathy (CTE), progressive supranuclear palsy (PSP), globular glial tauopathy (GGT), corticobasal degeneration (CBD), and Pick’s disease (PiD). Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.