RFC1 and cerebellar ataxia: The 2 novel cohorts independently suggest that RFC1 disease accounts for a substantial share of patients with so far unsolved ataxia, demonstrating this might be the case not only in cohorts expected to be phenotypically enriched for RFC1 disease (cohort A, 67%)1 but also for completely unselected “as-comes-in” late-onset ataxia cohorts (cohort B, 14%).