SOD1 and amyotrophic lateral sclerosis: Mice and rats expressing mutant forms of human SOD1 develop progressive MN degeneration and clinical signs that closely mimic human ALS (Gurney et al. 1994) and accordingly most of our knowledge of the etiology and pathogenesis of the disease is from studies carried out over the past 15 years using these animal models (see Rothstein 2009 for review).