SOD1 and amyotrophic lateral sclerosis: Fifteen percent of L5 ventral axons contained Hb9 driven MitoEGFP (Fig. 1G), all of which were the large-caliber (>4.5 μm; Fig. 1H) axons at-risk in ALS [18] and SOD1 mutant mediated ALS-like disease in mice [14].