Patients with SCA3 exhibit significantly higher serum, plasma and CSF NfL levels than those of unaffected controls (Wilke et al., 2018, 2020b; Li et al., 2019; Peng et al., 2022; Garcia-Moreno et al., 2022; Coarelli et al., 2021; Prudencio et al., 2020; Faber et al., 2023 preprint). The gene discussed is NEFL; the disease is Spinocerebellar ataxia type 3.