MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is the most prevalent dementia characterized by the presence of extracellular senile plaques, mainly consisting of aggregated amyloid-β (Aβ) and intraneuronal neurofibrillary tangles (NFTs), primarily composed of accumulated hyperphosphorylated and truncated tau, which are the cardinal pathological features in the brain.