Of the various neurodegenerative disorders in which abnormal accumulation, metabolism, and organization of Nfl proteins have been reported, amyotrophic lateral sclerosis (ALS), Parkinson’s disease (PD), and Charcot–Marie–Tooth (CMT) disease are among the best characterized [26,27,28] and will be discussed in the next sections. Here, NEFL is linked to amyotrophic lateral sclerosis.