Much of this earlier work lacked details regarding molecular mechanisms, including forms of DNA damage and types of DDR; however, the concept is now substantiated by this work and other studies of familial ALS mutant genes in cell culture, including SOD1, C9orf72, fused in sarcoma (FUS), and TAR DNA-binding protein 43 (TDP43) [23, 41, 87]. This evidence concerns the gene C9orf72 and amyotrophic lateral sclerosis.