NEFM and amyotrophic lateral sclerosis: Plasma concentrations of neurofilament proteins (Nf‐L and Nf‐H) and Nf Abs (Nf‐L, Nf‐M, and Nf‐H Abs) were elevated among ALS patients compared to HC‐1 (Fig. 1A and B; p < 0.0001).