NEFL and amyotrophic lateral sclerosis: The protein levels of neurofilament light chain (NF-L) and the phosphorylated form of neurofilament heavy chain (pNFH) were also consistently found to be increased in the CSF of ALS patients across multiple studies (Table S1), with a high level of either NF-L or pNFH predicting a shorter life expectancy (174–178).