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). The gene discussed is C9orf72; the disease is amyotrophic lateral sclerosis.