NEFL and amyotrophic lateral sclerosis: Different studies on sporadic ALS have demonstrated that elevated CSF and serum NfL, as well as elevated CSF phosphorylated neurofilament heavy chain (pNfH)—a different neurofilament subunit, are valid markers of the neurodegeneration taking place in ALS with potential implications in the differential diagnosis (Oeckl et al., 2016; Steinacker et al., 2016).