NFASC and amyotrophic lateral sclerosis: Among the purposed biomarkers for ALS, neurofilaments (Nf), existing in the high (NfH), middle (NfM), and low molecular weight (NfL), are a cytoskeletal structure specifically synthesized in neurons (Yuan et al., 2017); they are considered a surrogate marker of axonal injury, degeneration, and loss (Petzold, 2005).