Studies have shown high inter-subject variability in amyloid-β and tau patterns, however, and while most AD patients present high amyloid-β and high tau [37, 42], about 15–20% of amyloid-β-positive probable AD subjects have low tau levels [178]; this may relate to low binding site concentrations or the ability of tau tracers bind varied tau conformations [178]. Here, MAPT is linked to Alzheimer disease.