MAPT and frontotemporal dementia: In FTD, these form subtypes of frontotemporal lobar degeneration (FTLD) pathology: ∼40% of cases exhibit inclusions primarily composed of TDP-43 (encoded by TARDBP, FTLD-TDP), ∼40% with tau pathology (FTLD-tau), less frequently FTLD-FUS/FET with inclusions of the FET proteins FUS, EWS and TAF15, and finally FTLD-U of unknown composition.17 In ALS, the vast majority (∼97%) of cases exhibit TDP-43 pathology, with the remaining cases exhibiting SOD1 or FUS inclusions, all found both in lower and upper motor neurons.18