For example, in the zebrafish model of amyotrophic lateral sclerosis (ALS), overexpression of mutant SOD1 leads to aberrant branching and shortening of the primary motor axons (Lemmens et al., 2007), whereas knockdown of C9orf72, associated with ALS, causes aberrant branching of CaP motor axons (Ciura et al., 2013). This evidence concerns the gene SOD1 and amyotrophic lateral sclerosis.