TARDBP and frontotemporal dementia: Currently, four molecular subgroups of frontotemporal lobar degeneration (FTLD) have been established with FTLD-Tau being characterized by Tau depositions, FTLD-TDP by TDP-43 aggregates, and FTLD-FET by protein abnormalities of the FET (FUS, EWS, and TAF15) protein family.