Different biomarkers have been clinically validated to allow for a differential diagnosis of AD, such as CSF levels of total tau [93,94], the neuropathological hallmarks of this disease being the abnormal deposition of amyloid-β (Aβ) fibrils—the main component of senile plaques (SPs)—and the intracellular accumulation of neurofibrillary tangles (NFTs), composed of hyperphosphorylated tau protein (pTau) [95]. Here, MAPT is linked to Alzheimer disease.