One study examined FDG–PET and tau PET in two participants diagnosed with dysexecutive Alzheimer’s disease and showed frontal, parietal and temporal lobe hypometabolism that topographically overlapped with 18F-AV-1451 uptake (Dronse et al., 2017), whereas another study described one participant with dysexecutive/behavioural mixed phenotype with parietal 18F-AV-1451 uptake and no frontal uptake (Ossenkoppele et al., 2016). The gene discussed is MAPT; the disease is early-onset autosomal dominant Alzheimer disease.