To investigate G4C2/DPR-related TDP-43 pathology, novel Drosophila models of C9ALS/FTD, expressing different lengths of uninterrupted G4C2 repeats in the 3′ UTR of the disease-unrelated DsRed2 gene, were first created (Fig. 1A). The gene discussed is TARDBP; the disease is frontotemporal dementia.