Using PET radiotracers, imaging of tau deposits has become feasible lately and second generation tau-PET tracers such as [18F]PI-2620 [13] and [18F]PM-PBB3 [14] provide new possibilities to detect not only 3/4R-tau depositions typically found in Alzheimer’s disease (AD) but also have affinity to 4R-tau. Here, MAPT is linked to early-onset autosomal dominant Alzheimer disease.