TARDBP and frontotemporal dementia: Although our SCA31 studies highlighted novel roles of TDP-43, FUS, and hnRNPA2B1 as RNA chaperones for UGGAAexp RNA to modulate its folding and regulate the formation of toxic RNA aggregates (Figure 3), these RBPs on their own are known to play a toxic role in the pathogenesis of ALS/FTD (Ling et al., 2013).