MAPT and early-onset autosomal dominant Alzheimer disease: Alzheimer’s disease (AD) is a progressive neurodegenerative disease characterized by in its early stages the widespread neural deposition of amyloid-β (Aβ) plaques, followed by tau aggregation into neurofibrillary tangles in the regions such as entorhinal cortex which is part of Medial Temporal Lobe (MTL), and resulting in neurodegeneration, cognitive decline, and ultimately dementia [1–3].