MAPT and early-onset autosomal dominant Alzheimer disease: Accumulation of abnormal Tau in human brain has been implicated in major neurodegenerative diseases termed Tauopathies, including Alzheimer's disease (AD), Parkinson disease (PD), and Frontotemporal dementia with Parkinsonsim-17 (FTDP-17) (reviewed in refs 1, 2, 3).