MAPT and early-onset autosomal dominant Alzheimer disease: Hyperphosphorylation of the microtubule-associated protein tau–a pathological hallmark of Alzheimer's disease (Iqbal et al., 2016)– promotes abnormal translocation and accumulation of tau in the soma and aberrant assembly of microtubules, driving axonal transport deficits and other neurodegenerative effects (Majid et al., 2014; Morfini et al., 2016).