Expression of ALS-associated mutant SOD1, TDP-43, and FUS/TLS triggered mitochondrial fragmentation in mouse motor neurons, suggesting a further role of the mitochondrial fusion/fission balance in modulating pathogenesis (Magrane et al., 2009, 2012; Xu et al., 2010, 2011; Cozzolino et al., 2012; Tradewell et al., 2012). Here, SOD1 is linked to amyotrophic lateral sclerosis.