In patients with Alzheimer’s disease, temporo-parietal cortical tau PET signal is consistent with Braak stage III and above, while in cognitively healthy older individuals, the signal is localized to entorhinal cortex and inferior temporal cortex (Cho et al., 2016a; Johnson et al., 2016; for a review see Jagust, 2018). This evidence concerns the gene MAPT and early-onset autosomal dominant Alzheimer disease.