Since 22% of patients with hereditary ataxia in Taiwan have an unassigned genetic diagnosis, AVALD appears to account for a lower percentage (0.19%) of all hereditary ataxias in comparison to that of SCA3 (47%), SCA2 (11%), SCA6 (11%), SCA1 (5%), SCA17 (2.7%) in our population [45]. This evidence concerns the gene CACNA1A and hereditary ataxia.