A positive tau-PET visual read was associated with worse cross-sectional MMSE in CU participants (β = −0.85, CI −1.35 to −0.35, p = 0.001), but no significant cross-sectional association was observed in those with AD (β = −0.48, CI −1.05 to 0.08, p = 0.10). This evidence concerns the gene MAPT and Alzheimer disease.