Neurotoxicity in the chick spinal cord was comparable following G4C2 hexanucleotide and dipeptide electroporation, but we failed to detect any dipeptides from G4C2 repeat constructs, suggesting that both RNA foci and dipeptide repeats are contributing to the pathogenicity of the C9orf72 expansion in C9ALS/FTD. The gene discussed is C9orf72; the disease is frontotemporal dementia.