Due to the region-specific and variable patterns of tau PET, there is little consensus on how to quantify tau PET scans and incorporate them into the A/T/N scheme—a recommended category of AD biomarkers (A: β-amyloid biomarkers; T: tau biomarkers; N; neurodegeneration or neuronal injury biomarkers) [6]), as the region-of-interest (ROI) can be defined in various ways, and this can significantly influence study outcomes [21, 22]. This evidence concerns the gene MAPT and Alzheimer disease.