C9orf72 and amyotrophic lateral sclerosis: In the European ALS patients, the commonest mutations were the C9orf72 GGGGCC repeat expansions in fALS, among them, 33.7% of cases C9orf72, 14.8% of cases SOD1, 4.2% of cases TARDBP and 2.8% of cases FUS respectively.