Of note, stoichiometry of NF protein subunits (NEFL, NEFM and NEFH) has to be tightly controlled to avoid the formation of NF neuronal cytoplasmic inclusions, axonal degeneration and neuronal death, all pathological hallmarks of motoneuron disorders such as amyotrophic lateral sclerosis (ALS).26 This evidence concerns the gene NFASC and amyotrophic lateral sclerosis.