MAPT and Alzheimer disease: The current in vivo results are in line with the abundant literature based on neuropathology showing that the presence of multiple pathologies is the norm rather than the exception with advanced age and neurodegenerative diseases20,21 and recent studies on patients with low tau-PET levels.22,23 These results are also important in relation to clinical trials and antiamyloid therapies,24 where the presence of copathologies might influence (and lower) the response to drugs targeting AD pathology.