Neurodegenerative diseases such as prion diseases, amyotrophic lateral sclerosis (ALS), Alzheimer’s disease, Parkinson’s disease, Hungtington’s disease, and traumatic brain injury have all demonstrated increased levels of NfL (Bridel et al., 2019; Gaetani et al., 2019a). The gene discussed is NEFL; the disease is amyotrophic lateral sclerosis.