SOD1 and amyotrophic lateral sclerosis: The main cause of the onset of ALS is due to the mutations in Cu/Zn superoxide dismutase gene (SOD1), mutations in the fused in sarcoma gene (FUS)—which encodes a protein responsible for DNA repair and related to juvenile-onset forms of the disease—or TAR DNA-binding protein 43 gene (TDP-43)—a key protein for the repair pathways of DNA double-strand breaks in motor neurons and oligodendrocytes [6,20,29,30,31,32].