MAPT and early-onset autosomal dominant Alzheimer disease: Tauopathies, such as frontotemporal dementia (FTD), progressive supranuclear palsy (PSP) and Alzheimer’s disease (AD), are a group of neurodegenerative diseases characterized by the pathological accumulation of hyper-phosphorylated tau (P-tau) protein, in the form of intracellular paired helical filaments (PHFs) or neurofibrillary tangles (NFTs), within neurons and glia of affected brain regions, leading to cell death (Kosik et al., 1989; Morris et al., 2011; Cruts and Van Broeckhoven, 2015; Ghetti et al., 2015; Neumann et al., 2015; Olney et al., 2017; Goedert, 2004).