In amyotrophic lateral sclerosis, accumulating evidence indicates that a mechanism for the progressive accumulation of misfolded mutant form of superoxide dismutase 1 (SOD1) is cell-to-cell propagation of SOD1 within the brain via extracellular vesicles that extend the range and toxicity during disease [7, 8]. The gene discussed is SOD1; the disease is amyotrophic lateral sclerosis.