RYR2 and autosomal dominant cerebellar ataxia: Of the 14 SUDY victims with functionally characterized RYR2 variants, five (2% of total cohort) had a LOF variant; among the 56 exertion-related SUDY cases, four (7%) had a LOF variant.<h4>Conclusion</h4>CRCDS may account for 3% of IVF overall and 9% of exertion-related SCA in IVF.