Indeed, studies on tau-PET with 18F-Flortaucipir showed that (i) Braak stages, representing tau load and topography, better correlate with clinical symptoms than amyloid load [29, 31, 32]; (ii) its positivity indicates both advanced amyloid and tau neuropathology [23]; (iii) it proved to be able to differentiate between amyloid-positive and amyloid-negative neurodegenerative diseases with high accuracy [33]; (iv) tau deposition is closely related to other markers of neuronal injury, e.g., FDG-PET and gray matter atrophy [34–36]. This evidence concerns the gene MAPT and amyloidosis.