This group reported a mild but significant binding of tracer in amyloid negative MAPT mutation patients, highlighting that a positive [18F]MK-6240 tau-PET does not imply with certainly an AD diagnosis [93], and pointing towards a potential use of Tau tracers as a biomarker in tauopathies beyond AD, even with some limitations due to the modest affinity. The gene discussed is MAPT; the disease is Alzheimer disease.