To date, several PET ligands including [11C]PBB3, [18F]THK5105, [18F]THK5117, [18F]THK5351 [18F]T807 and [18F]T808 have been tested to image tau neurofibrillary tangle deposition in living AD patient brains [12–14, 15••]. This evidence concerns the gene MAPT and Alzheimer disease.