MAPT and early-onset autosomal dominant Alzheimer disease: Tau protein was first isolated at Kirschner’s lab in 1975 [4] and from that year up to 1988, the study of tau shifted from that of a microtubule-associated protein [5,6,7,8] to that of a component of the paired helical filaments found in the brain of Alzheimer’s disease (AD) patients [9,10,11,12,13,14,15,16,17,18].