C9orf72 and frontotemporal dementia: Likewise, for ALS/FTD, deposits of Tar DNA-binding protein 43 (TDP-43), Fused in Sarcoma (FUS), and dipeptide repeat proteins derived from the C9ORF72 gene are major pathologies, and mutations in TDP43, FUS, and C9ORF72 cause dominantly inherited forms of disease [1].