TARDBP and behavioral variant of frontotemporal dementia: Frontotemporal dementia (FTD) is a common cause of early onset dementia presenting clinically with behavioural change (behavioural variant FTD (bvFTD)) or language impairment (primary progressive aphasia (PPA)) and pathologically, with inclusions containing usually either tau or TAR DNA-binding protein 43 (TDP-43).