To further test the “distinct cortical” hypothesis, we re-analyzed the data available from Whitwell et al. [11], Charil et al. [6], and Young et al. [12], and investigated the ADNI cohort so as to identify hippocampal sparing AD participants who had normal tau PET uptake values in the hippocampus or entorhinal cortex (see next section). This evidence concerns the gene MAPT and Alzheimer disease.