MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer's disease (AD), the most incident age-related neurodegenerative disorder with cognitive impairment, is characterised by progressive brain atrophy and the presence of intracellular neurofibrillary tangles consisting of hyperphosphorylated tau protein and extracellular senile plaques composed of amyloid-beta (Aβ) peptide and neuroinflammation [46].