C9orf72 and amyotrophic lateral sclerosis: Among Asian populations, in Chinese ALS patients, in which C9orf72 repeat expansion account for 0–1.5% of SALS and 5.98% of FALS, SOD1 gene has been revealed as the most common causative gene, accounting for 1.45% of SALS and 25.33% of FALS [43].