MAPT and early-onset autosomal dominant Alzheimer disease: The dominant hypothesis of the etiology of Alzheimer's disease, neuropathological guidelines for the diagnosis of the disease, and most of the wide-ranging therapeutic efforts, both in research and clinical practice, have been built around the amyloid and tau proteins as causal factors (Ittner and Ittner, 2018; Busche and Hyman, 2020; Uddin et al., 2020).