C. elegans has been used to model the four most common ALS-causing mutations in C9orf72-SMCR8 complex subunit (C9orf72), superoxide dismutase (SOD1), TAR DNA-binding protein (TARDBP) and RNA-binding protein FUS/TLS (FUS), as well as a mutation associated with FTD [microtubule-associated protein tau (MAPT)]. The gene discussed is C9orf72; the disease is frontotemporal dementia.