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
If cord blood is submitted, maternal cell contamination (MATCC) studies may be required and performed at additional charge. For New York clients, informed consent documentation is required (e.g., T576 or T826 forms) and must be on file or submitted. Order forms include Neurology Specialty Testing Client Test Request (T732) if ordering non‑electronically.
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
- 21769-5
- 36911-6
- 69047-9
- 48767-8
- 31208-2
- 85069-3
- 62364-5
- 18771-6
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 |