Several variants of familial neurodegenerative disorder amyotrophic lateral sclerosis have been linked with SOD-1 mutations, affecting metal-binding sites occupied by Cu2+ and Zn2+ and leading to distorted SOD-1–SOD-1 interactions, leading to formation of insoluble aggregates described above [262]—a phenomenon that can also be propagated from cell to cell [263]. Here, SOD1 is linked to amyotrophic lateral sclerosis.