Since pioneering studies detecting elevated levels of Nfs (specifically of the NfL subunit) in the CSF of patients with Alzheimer’s disease and ALS [16], extensive research on Nfs has resulted in its emergence as an unspecific marker of acute and chronic axonal damage in the generic field of neurology, encompassing different types of insults to the central nervous system and, to a lesser extent, peripheral nervous system [17,18]. The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.