Spinocerebellar Ataxia Expansion Panel

Test Information

This panel of 5 genes is intended for patients with a diagnosis or clinical suspicion of spinocerebellar ataxia, and it is performed by trinucleotide repeat expansion analysis.

Turnaround Time

21 days

CPT Code(s)

81178, 81179, 81180, 81184, 81181




  • ATXN1
  • ATXN2
  • ATXN3
  • ATXN7

Clinical Information

Spinocerebellar ataxia (SCA) refers to a group of neurodegenerative disorders that affect the cerebellum, the region of the brain that controls the coordination of movement. SCA is marked by progressive ataxia or poor coordination of movement. Other features include unsteady gait, poor hand coordination, involuntary eye movements, and slurred speech. Cognitive decline can be seen in certain types of SCA. The age of onset of SCA is extremely variable and ranges from childhood to late adulthood. Trinucleotide repeat expansions are one genetic cause for SCA with SCA 1, 2, 3, 6, and 7 accounting for ~60% of dominant ataxias in North America. These ataxias result from trinucleotide repeat expansion, and the size of the repeat expansion is typically correlated with age on onset and rate of progression.


Triplet repeat-primed PCR


Trinucleotide repeat expansion in one of these genes is responsible for approximately 60% of spinocerebellar ataxias.

Specimen Requirements

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Have Questions? Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC

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