C9orf72 and frontotemporal dementia: While most cases occur sporadically, there are many genes associated with ALS/FTD, including SOD1 (superoxide dismutase 1), FUS (fused in sarcoma), TAU (tubulin associated unit), TDP-43 (TAR-DNA-binding protein 43), and C9orf72 (Chromosome 9 open reading frame 72) [64,65,66,67,68,69,70,71].