Importantly, the phenotype of C9ALS/FTD fibroblasts and induced pluripotent stem cell neurons was recapitulated by C9orf72 and RAB7L1 knockdown in SH-SY5Y cells, as confirmed by a reduced amount of the exosome-specific markers ALIX and TSG101 and exosome surface antigens CD9, CD63 and CD81. The gene discussed is C9orf72; the disease is frontotemporal dementia.