SOD1 and amyotrophic lateral sclerosis: Remarkably, recent advances using induced-pluripotent-stem-cell (iPSC)-derived motor neurons from ALS patients carrying SOD1 mutations have recapitulated essential disease features in the absence of mutant SOD1 aggregation, consistent with the idea that soluble mutant proteins can have substantial phenotypic effects ([65,66,67], reviewed in [68]).