MAPT and early-onset autosomal dominant Alzheimer disease: Pathological species of microtubule-associated protein tau (MAPT)1 accumulate in the brain of Alzheimer’s disease (AD) and diverse non-AD neurodegenerative disorders collectively referred to as tauopathies, including frontotemporal lobar degeneration (FTLD) characterized by tau deposition (FTLD-tau)2.