MAPT and Alzheimer disease: The mechanisms through which LC degenerates in PD and AD differ: in AD, it is related to progressive accumulation of Tau pathology, starting from hyperphosphorylated TAU (pTAU) up to neurofibrillary tangles (NFT) [8], while in PD, it is related to Lewy-body pathology (i.e., to alpha-synuclein accumulation) [9].