SOD1 and amyotrophic lateral sclerosis: The NfL-ALSPR index for C9orf72 ALS was the highest among all investigated genetic ALS (5.02 ± 0.88), followed by SOD1 ALS (4.94 ± 1.03), FUS (4.9 ± 0.91) and TARDBP (4.4 ± 0.7) (Table 1).