These ALS cases (fALS), which clinically and pathologically are indistinguishable from the sporadic form, frequently show either point mutations in the genes coding Cu/Zn-binding superoxide dismutase 1 protein (SOD1) 108, the TAR DNA binding protein 43 (TDP-43) 96, 109, 110, the RNA-binding protein Fused in Sarcoma (FUS) 111, 112 or hexanucleotide expansions in the first intron of the C9orf72 gene 113, 114. Here, FUS is linked to amyotrophic lateral sclerosis.