NEFL and neuropathy: An explanation of this phenomenon is that NfL may increase rapidly in the initial stages of the disease and then reach a plateau above a certain degree of severity, as observed in other genetic ataxias.12, 13, 18 Other possible explanations entail the difficulty in accurately defining the onset of the disease, because neuropathy symptoms may remain unnoticed for a long time, or the chronologically variable involvement of the cerebellum in early or late disease stages relative to onset, due to factors yet to be explored, including the repeat size and additional genetic modifiers.