As described by Jack et al. [80], the prevalence of positive biomarkers in the Mayo Clinic Study on Aging, among 1524 participants who had Aβ PET and 576 participants who had tau PET, increased exponentially with age for both Amyloid PET and Tau PET, and the prevalence exceeded the prevalence of clinically defined probable AD. This evidence concerns the gene MAPT and Alzheimer disease.