NEFL and amyotrophic lateral sclerosis: Among several candidates, neurofilament light chain (NfL), a validated marker of neuroaxonal damage that can be reliably measured in both CSF (cNfL) and plasma (pNfL) (Gray et al., 2020), showed the best performance in distinguishing patients with ALS from patients with ALS mimics (Steinacker et al., 2016; Poesen et al., 2017; Feneberg et al., 2018;Gille et al., 2019; Abu-Rumeileh et al., 2020; Ashton et al., 2021).