NEFL and amyotrophic lateral sclerosis: Identifying specific biomarkers to aid disease diagnosis and prognosis, particularly in terms of distinguishing ALS from disease mimics, classifying disease subtypes and predicting disease progression, has been undertaken by ourselves and others.3-5 Identifying biomarkers, such as neurofilament light (NfL), a known ALS pathological marker reflecting axonal degeneration may also help our understanding of ALS pathology and has also been used to monitor patient’s response to drugs and therapeutic agents.6-8