We argue, these results do not only indicate a greater clinical utility of temporo-orbital reference regions in applications for differential diagnosis of patients with suspected 4R tauopathies but may also facilitate the discovery of novel PSP biomarkers (e.g. fluid) using [18F]PI-2620 PET imaging as an established 4R tau quantification method. This evidence concerns the gene MAPT and supranuclear palsy, progressive, 1.