SOD1 and amyotrophic lateral sclerosis: Supporting the involvement of the second route, it has also been reported that muscle precursor cells derived from skeletal muscle biopsies of ALS patients show both altered morphology and impaired regenerative capabilities [32,33], and, even more remarkably, the muscle-specific overexpression of mutant hSOD1 is sufficient to produce a reliable panel of ALS disease phenotypes in a Tg mouse model [34,35,36,37,38].