SOD1 and amyotrophic lateral sclerosis: The study of these four genes and their proteins SOD1, TDP-43, FUS, and TBK1 provides a better understanding of their physiological roles in the different cell types of the central nervous system and their roles in the pathophysiology of ALS, with the aim of developing new therapeutic approaches, for example, by targeting the molecular pathways involving these proteins but also by specifically targeting these causal genes or their expression at mRNA or protein level.