OPTN and frontotemporal dementia: Regarding the genetics, clinical clusters of FTD and ALS have been reported to be associated with several genes, including granulin precursor (GRN) [15, 42], valosin-containing protein (VCP) [153], TAR DNA-binding protein (TARDBP) [85, 91], chromosome 9 open reading frame 72 gene (C9orf72) [45, 100, 124], sequestosome 1 (SQSTM1) [148], ubiquilin 2 (UBQLN2) [46], TANK-binding kinase 1(TBK1) [56], T cell-restricted intracellular antigen-1 gene (TIA1) [103], cyclin F (CCNF) [158], coiled-coil-helix-coiled-coil-helix domain-containing protein 10 (CHCHD10) [16] and optineurin (OPTN) [35].