Based on the neuropathological similarity of the tau NFT in PRNP F198S GSS and AD [33], we hypothesized that [18F]flortaucipir, a recently developed PET tracer that is specifically sensitive to tau NFTs [2, 37], would permit in vivo detection of tau deposits in PRNP F198S GSS patients. This evidence concerns the gene MAPT and Alzheimer disease.