C9orf72 and frontotemporal dementia: A total of 8 genes have been identified as causative genes of both familial and sporadic FTD patients, including microtubule-associated protein tau (MAPT)9, progranulin (GRN)10, chromosome 9 open-reading frame 72 (C9orf72)11, chromatin modifying protein 2B (CHMP2B)12, TAR DNA-binding protein (TARDBP)13, valosin-containing protein (VCP)14, fused in sarcoma (FUS)15, and coiled-coil-helix-coiled-coil-helix domain containing 10 (CHCHD10)16.