MAPT and early-onset autosomal dominant Alzheimer disease: Tauopathies are a heterogeneous class of neurodegenerative diseases including Alzheimer’s disease (AD)1, chronic traumatic encephalopathy (CTE)2, progressive supranuclear palsy (PSP)3, corticobasal degeneration (CBD)4, and Pick’s disease (PiD)5, characterized by the formation of aggregated filaments of microtubule associated protein tau in the brain.