Spinocerebellar Ataxia Repeat Expansion Analysis
Use
This test evaluates CAG repeat expansions in multiple ATXN genes (ATXN1, ATXN2, ATXN3, ATXN7, ATXN8) and the CACNA1A gene associated with spinocerebellar ataxia types 1, 2, 3, 6, 7, and 8, providing molecular confirmation of clinically suspected SCA subtypes when the specific type is unclear or multiple possibilities exist.
Special Instructions
Orderable as part of GeneDx's neurology test menu; requires appropriate requisition. Multiple single-gene SCA repeat analyses (e.g., TH84–TH89 for specific ATXN types) are also available as alternative ordering options.
Limitations
Repeat expansion testing may not detect interruptions or mosaicism reliably; expansions beyond certain repeat sizes may not be fully resolved. Interpretation may be affected by technical factors including allele dropout and DNA quality; specificity and sensitivity dependent on fragment analysis.
Methodology
PCR-based (PCR)
Biomarkers
Result Turnaround Time
14-21 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
Not provided
Minimum Volume
Not provided
Container
Lavender top (EDTA) tube
Other tests from different labs that may be relevant