MAPT and Alzheimer disease: Despite finding elevated plasma NFL in cortical–basal syndrome, progressive supranuclear palsy, behavioural variant frontotemporal dementia and Alzheimer’s disease compared to healthy controls, Thijssen et al. (2020) found that plasma NFL was not related to either tau PET (flortaucipir) or Aβ PET (PiB/florbetapir).