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 12 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 12 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, FXN, NOP56, PPP2R2B, and TBP genes

Optionally includes:

Included Genes


This test covers many disorders including:

  • Congenital hypotonia, epilepsy, developmental delay, and digital anomalies
  • 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

Short tandem repeats:

Due to the variable nature of repetitive sequences and sequence-specific differences in detection and repeat evaluation, orthogonal confirmation is performed on a case-by-case basis. Reportable pathogenic or intermediate repeat expansions may be reported with or without repeat count.

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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