For example, protein aggregates containing amyloid-beta, huntingtin, and mutant form of superoxide dismutase 1 (SOD1) are respectively associated with neurodegenerative diseases, such as Alzheimer’s disease2,3, Huntington’s disease4–6, and a form of familial amyotrophic lateral sclerosis (ALS)3,7. This evidence concerns the gene SOD1 and familial amyotrophic lateral sclerosis.