NEFL and autosomal dominant cerebellar ataxia: NfL is a protein mostly concentrate in neuronal axons, where it plays a crucial role in maintaining stability, shape and regulation of the axon's diameter, while in case of axonal damage, it is released into cerebrospinal fluid and in blood.5 NfL levels have been measured in various types of genetic ataxia,6 including autosomal dominant spinocerebellar ataxias (SCAs),7-9 and FRDA.10-13 In patients with SCAs, NfL concentrations are elevated in comparison to healthy controls, and blood levels progressively increase during the course of the diseases.