Supporting the latter idea is evidence that 11C-PBB3 appears to capture 4-repeat isoform tau specific to progressive supranuclear palsy and Pick’s disease, whereas 18F-AV-1451 may be better at capturing 3- and 4-repeat tau isoforms present in AD (Lowe et al., 2016; Sander et al., 2016; Ono et al., 2017). Here, MAPT is linked to Alzheimer disease.