SOD1 and amyotrophic lateral sclerosis: Axonal transport (retrograde and anterograde) is impaired in ALS patients and in mutant SOD1 mice, as evidenced by the accumulation of altered structures, such as mitochondria, neurofilaments, and autophagosomes, in the spinal motor neuron axons (Ikenaka et al., 2012; Zarei et al., 2015).