The AT(N) research framework focused on biomarkers in living persons, grouped into those representing β amyloid (Aβ) or “A”, pathologic tau or “T”, and neurodegeneration or “(N)”, which is defined by the underlying pathologic processes in the pathology of AD, that define the disease at postmortem examination and can be assessed in vivo by biomarkers. This evidence concerns the gene MAPT and Alzheimer disease.