MAPT and Alzheimer disease: Studies with CI participants included populations with risk factors for AD, that is (1) amnestic or non-amnestic MCI participants (Petersen et al., 1999) and (2) participants with objective CI associated with neurodegeneration biomarkers based on imaging [medial temporal lobe atrophy or hypometabolism on 18F-fluorodeoxyglucose (18F-FDG) positron emission tomography (PET) data] or CSF compounds (abnormal levels of Aβ peptides, Aβ1 − 42, Aβ1 − 40, Aβ1 − 42/1 − 40 ratio; t-Tau, or p-Tau181; n = 3; Dubois et al., 2007; Albert et al., 2011).