MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) represents the most prevalent type of dementia in elderly people [1], primarily characterized by brain accumulation of beta-amyloid (Aβ) peptide in the extracellular space (amyloid plaques) and intracellular deposits of paired helical filaments (PHF), mainly formed by the hyperphosphorylated form of the protein tau (p-tau) (tangles or neurofibrillary aggregates) [2,3].