MAPT and Alzheimer disease: AD, pathologically characterized by the deposition of amyloid β (Aβ) peptide and neurofibrillary tangles formed by tau proteins in the brain, is the most common cause of dementia in elderly individuals.174 Breakdown of the BBB, a highly specialized brain endothelial structure of the fully differentiated neurovascular system, seems to be involved in the etiopathology of AD.