NEFL refers to the neurofilament light polypeptide, a low molecular weight neurofilament protein. Neurofilaments are intermediate filaments that form the neuronal cytoskeleton together with microtubules. They act as structural space-fillers for axons and are also involved in axonal transport. Antibodies that detect NEFL are regularly used to identify neurons and distinguish them from glia (neurofilament-negative) and for diagnosis in neuropathology. Because neurofilaments are released into the blood and cerebrospinal fluid when axons and neurons deteriorate, antibodies can also be used to observe the progression and state of neurodegenerative diseases such as multiple sclerosis and Huntington’s disease. NEFL is also specifically implicated in Charcot-Marie-Tooth disease, described by a mutation-induced knockout of the gene that results in childhood-onset neuropathy. In immunohistochemistry, NEFL antibodies are positive in axons of neuronal cells in the central nervous system and in peripheral nerves. References: European Journal of Neurology. 2010 Mar. 17 (3): 377–8, PMID: 19845747; Neurology. 2009 Apr. 72 (15): 1322–9, PMID: 19365053; PLOS One. 2017 Feb. 12 (2): e0172762, PMID: 28241046; Garland Science. ISBN: 978-0-8153-3218-3; Neurology Genetics. 2018 June; 4 (3), DOI: 10.1212/NXG.0000000000000244; Brain. 2003 Mar. Volume 126, Issue 3; 590–597, DOI: 10.1093/brain/awg059