The severe early-onset ataxias seen in these patients are similar to reports of severe early-onset ataxia associated with CACNA1A missense variants observed in the S4 transmembrane segment of domain III (e.g. p.I1342T, p.V1396M, and p.R1352Q) [27] or domain IV (R1664Q) [34]. This evidence concerns the gene CACNA1A and Ataxia.