Studies selected for meta-analysis of the modulation of age at onset in SCA3/MJD by CAG repeat length at ATXN3 and additional factors
| Cohort | N, published* | N, available† | Data type | QC programme‡ | Available data (risk factors) | Reference |
| Rio Grande do Sul, Brazil | 463 | 507 | IPD | Yes | Family, gender, origin, ATXN3, ATXN1, ATXN2, CACNA1A, ATXN7 | Souza et al 23 2016 |
| EUROSCA, Europe | 403 | 403 | IPD | Yes | Family, gender, origin, ATXN3, ATXN1, ATXN2, CACNA1A, ATXN7 | Tezenas du Montcel et al 6 2014 |
| Taiwan | 48 | 347 | IPD | NS | Gender, origin, ATXN3 | Wang et al 19 2012 |
| Portugal (Mainland) | 48 | 226 | IPD | Yes | Origin, ATXN3 | Silveira et al 17 1998 |
| China | 141 | 141 | IPD | NS | Family, origin, ATXN3 (expanded allele only) | Wang et al 20 2017 |
| Netherlands | 342§ | 133 | IPD | Yes | Family, origin, ATXN3 | van de Warrenburg et al 18 2005 |
| São Paulo, Brazil | 34 | 110 | IPD | No | Origin, ATXN3 (expanded allele only) | França Jr et al 22 2009 |
| Portugal (Azorean Islands) | 93 | 106 | IPD | Yes | Family, gender, origin, ATXN3, ATXN1, ATXN2, CACNA1A, ATXN7 | Raposo et al 7 2015 |
| Neurogenetics network, Brazil | 481¶ | 104 | IPD | Yes | Family, gender, origin, ATXN3, ATXN1, ATXN2, CACNA1A, ATXN7 | de Castilhos et al 5 2014 |
| Cuba | 22 | 22 | IPD | Yes | Origin, ATXN3 | González-Zaldívar et al 21 2015 |
| China | 802 | AD | NS | Origin, ATXN3 (expanded allele only) | Chen et al 8 2016 | |
| USA | 110 | AD | NS | Origin, ATXN3 (expanded allele only) | Tezenas du Montcel et al 6 2014 |
*Number of patients reported on the original publication.
†Number of patients whose data were obtained after contacting the corresponding author of the selected publication.
‡Participation in molecular diagnosis quality control programme.
§This study reports on Dutch and French patients, but only the Dutch cohort was available for analysis.
¶This study includes patients from the Rio Grande do Sul cohort, but only patients from other Brazilian regions were retrieved for analysis.
AD, aggregated database; EUROSCA, European Consortium on Spinocerebellar Ataxias; IPD, individual-participant database; NS, not specified; SCA3/MJD, spinocerebellar ataxia type 3/Machado-Joseph disease.