| Prevalence | Rare (~1 per 100,000) |
| Inheritance | Autosomal dominant |
| Age of onset | Highly variable (1-70 years, mean ~30 years) |
| Penetrance | Incomplete (~90% by age 60) |
| Sex ratio | Equal male/female |
| Geographic distribution | Worldwide, all ethnicities |
| Gene | ATXN8OS (Ataxin-8 opposite strand) |
| Alternative names | OSCA, SCA8OS |
| Chromosome | 13q21.31 |
| Normal repeat | 15-50 CTG repeats |
| Pathogenic repeat | 71-1,300 CTG repeats |
| Intermediate (reduced penetrance) | 50-70 repeats |
| Databases | OMIMOrphanetClinicalTrialsPubMed |