NEFL and cerebellar ataxia: Studies in patients with SCA3 have demonstrated trends for NfL increases between the pre-ataxic stage and symptomatic ataxia onset (Wilke et al., 2020b; Li et al., 2019; Peng et al., 2022; Faber et al., 2023 preprint), and stably increased NfL levels during the symptomatic ataxic phase.