Plasma levels of p-tau217 have been shown to associate with brain tau pathology specifically found in the presence of Aβ plaques in postmortem tissue [16, 19], which is in agreement with imaging studies demonstrating correlations between plasma p-tau217 and tau- positron emission tomography (PET) in patients with AD, but not in non-AD tauopathies [10, 19, 22]. This evidence concerns the gene MAPT and Alzheimer disease.