MAPT and Alzheimer disease: The notion that the preclinical period of sporadic Alzheimer’s disease (AD), the most common late-life dementia, can last for decades is supported by studies involving MRI and positron emission tomography (PET), which indicate that there are synergistic relations between tau protein deposition, amyloid β peptide (Aβ) plaques, and neurodegeneration [1,2,3,4].