MAPT and tauopathy: As diagnostic groups we selected bvFTD, which is largely associated with either FTLD-tau or FTLD-TDP-43 pathology, PSP based on its association with 4R tau pathology, Alzheimer disease (AD) as a secondary tauopathy with equally balanced 3R and 4R tau pathology, and svPPA and ALS as disorders with almost exclusive TDP-43 pathology, in addition to healthy controls (HC).