C9orf72 and frontotemporal dementia: Clinical and molecular overlap between FTD and ALS exists with mutations in C9orf72, TARDBP, FUS, TANK-binding kinase 1 (TBK1), valosin containing protein (VCP), coiled-coil-helix-coiled-coil-helix domain containing 10 (CHCHD10), and sequestosome-1 (SQSTM1) [54], suggesting that the two disorders share common pathophysiological mechanisms.