Spinocerebellar Ataxia Repeat Expansion Panel, Varies
Use
Molecular confirmation of clinically suspected spinocerebellar ataxia when a specific subtype isn’t suspected. The test assesses for CAG repeat expansions within ATXN1, ATXN2, ATXN3, CACNA1A, and ATXN7 genes, associated with SCA type 1, 2, 3, 6, and 7; additionally assesses for CAT trinucleotide interruptions in the ATXN1 CAG repeat tract.
Special Instructions
Not provided.
Limitations
Due to somatic mosaicism, repeat size in peripheral blood may not reflect untested tissues (e.g., CNS). A negative result does not exclude mosaic variants below detection (~10%). Rare sequence variants near primer-binding regions may interfere and produce false negatives.
New York Approved
Methodology
PCR-based (PCR)
Biomarkers
LOINC Codes
- 21769-5 - SCA genes CAG Rpt Bld/T Ql
- 21769-5 - SCA genes CAG Rpt Bld/T Ql
- 36911-6 - SCA gene Mut Anl Bld/T
- 69047-9 - Geneticist review
- 48767-8 - Annotation comment Imp
- 31208-2 - Specimen source
- 85069-3 - Lab test method
- 62364-5 - Test performance info Spec
- 18771-6 - Provider signing name
Result Turnaround Time
21-28 days
Related Documents
For more information, please review the documents below
Specimen
Whole Blood
Volume
3 mL
Minimum Volume
Not provided
Container
Lavender top (EDTA) or yellow top (ACD)
Collection Instructions
Invert several times to mix blood; send whole blood in original tube; do not aliquot. Umbilical cord whole blood also acceptable.
Patient Preparation
A previous hematopoietic stem cell transplant from an allogeneic donor will interfere with testing.
Stability Requirements
| Temperature | Period |
|---|---|
| Room Temperature | 4 days |
| Refrigerated | 4 days |
| Frozen | 4 days |