PFN1 and amyotrophic lateral sclerosis: To date, a large number of genes have been linked to ALS, including Cu/Zn superoxide dismutase (SOD1)4, TAR DNA-binding protein (TDP-43)5 fused in sarcoma (FUS)6, sequestosome 1 (p62/SQSTM1)7, optineurin (OPTN)8, TANK binding kinase 1 (TBK1)9, VAMP-associated protein B (VAPB)10, valosin-containing protein (VCP)11, ubiquilin 2 (UBQLN2)12, alsin (ALS2)13, charged multivesicular body protein 2B (CHMP2B)14, dynactin (DCTN)15, profilin 1 (PFN1)16, factor-induced gene 4 (FIG4)17, and a hexanucleotide repeat expansion in the gene C9orf7218.