Genomic Unity® Ataxia Repeat Expansion Analysis

Test Description

Test Code – NR003

Ataxias are a group of neurological conditions most often related to degeneration of the cerebellum, the part of the brain that coordinates movement. Ataxias can affect different parts of the body, speech, eye movements, and balance.

Genomic Unity® Ataxia Repeat Expansion Analysis uses a whole genome sequencing platform to diagnose genetic causes of ataxia due to tandem repeat expansions in 13 genes. For a broader analysis of ataxia-related genes beyond this repeat expansion analysis, consider the Genomic Unity® Comprehensive Ataxia Analysis.

When to Order

Order this test when clinical symptoms are consistent with ataxia and you’d like to specifically test the 13 repeat expansion loci. You also have the option to reflex up to Genomic Unity® Exome Analysis or Genomic Unity® Exome Plus Analysis if targeted analysis is non-diagnostic.

Included Analyses

  • Sequence analysis of ataxia tandem repeat genes (single nucleotide variants, deletions, insertions, and characterized intronic variants)
  • Copy number variant analysis of ataxia tandem repeat genes (duplications/deletions, mobile element insertions, and inversions)
  • Short tandem repeat (STR) analysis of the ATN1, ATXN1, ATXN2, ATXN3, ATXN7, ATXN8OS, ATXN10, CACNA1A, FMR1, FXN, NOP56, PPP2R2B, and TBP genes

Optionally includes:

Included Genes

Note: The ATXN7 gene is not fully covered by this test, therefore not all pathogenic variants may be detected. The false negative rate has not been determined for repeat expansions for ATXN10, NOP56 and TBP.


This test covers many disorders including:

  • Congenital hypotonia, epilepsy, developmental delay, and digital anomalies
  • Fragile X–associated tremor/ataxia syndrome
  • Dentatorubral-pallidoluysian atrophy
  • Spinocerebellar ataxia type 1
  • Spinocerebellar ataxia type 2
  • Spinocerebellar ataxia type 7
  • Spinocerebellar ataxia type 8
  • Spinocerebellar ataxia type 10
  • inocerebellar ataxia type 12
  • Spinocerebellar ataxia type 17
  • Spinocerebellar ataxia type 36
  • Episodic ataxia type 2
  • Developmental and epileptic encephalopathy type 42
  • Machado-Joseph disease
  • Friedreich’s ataxia

Test Performance

Sensitivity for SNVs
 >  %
Specificity for SNVs
Positive predictive value for SNVs
Clinical sensitivity for structural variants
Clinical sensitivity for STRs

CPT Codes


The CPT codes provided are for informational purposes only. CPT coding is the sole responsibility of the billing party. Please direct any questions regarding coding to the payer being billed.

Accepted Specimens







Turnaround Time

A report will be issued within 4 weeks from receipt of required samples.

Contact Us

Please contact customer service to request a kit.

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