PET imaging with 2-(2-([18F]fluoro)pyridin-4-yl)-9H-pyrrolo[2,3-b:4,5-c′]dipyridine ([18F]PI-2620) has demonstrated the ability to detect tau pathology in patients diagnosed with progressive supranuclear palsy (PSP) (1) and corticobasal syndrome (2,3). The gene discussed is MAPT; the disease is progressive supranuclear palsy.