Further, SOD1, C9orf72, and SMN1 have been identified as causative genes for amyotrophic lateral sclerosis and spinal muscular atrophy, in which the viability of spinal motor neurons is decreased [5,77], and treatment strategies targeting these genes are under development [78,79,80]. The gene discussed is C9orf72; the disease is proximal spinal muscular atrophy.