NEFL and amyotrophic lateral sclerosis: In past 25 years [21], a number of protein biomarkers have been linked to ALS such as Polydipeptide Repeats (DPRs), Neurofilament Heavy Chain (Nf-H), Neurofilament Light Chain (Nf-L), and Phosphorylated Neurofilament Heavy (pNfH) and Light Chain (pNfL) [22].