MAPT and amyotrophic lateral sclerosis: The study included several diagnostic groups: ALS characterized by TDP-43 proteinopathy, progressive supranuclear palsy (PSP) characterized by 4R tau-dominant tauopathy, and bvFTD patients with either tau or TDP-43 pathology (classified as FTLD-tau and FTLD-TDP groups, respectively), along with healthy controls.