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Episodic Ataxia Type 1 or Hypomagnesemia via the KCNA1 Gene

Summary and Pricing

Test Method

Sequencing and CNV Detection via NextGen Sequencing using PG-Select Capture Probes
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
9249 KCNA1 81479 81479,81479 $990 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
9249KCNA181479 81479,81479 $990 Order Options and Pricing

Pricing Comments

This test is also offered via our exome backbone with CNV detection (click here). The exome-based test may be higher priced, but permits reflex to the entire exome or to any other set of clinically relevant genes.

An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.

Testing run on PG-Select capture probes does not include exome-wide CNV analysis. Reflex is available to PGxome or an exome-based panel, or you can use this gene list to create a custom panel (click here).

Click here for costs to reflex to whole PGxome.

Turnaround Time

3 weeks on average for standard orders or 2 weeks on average for STAT orders.

Please note: Once the testing process begins, an Estimated Report Date (ERD) range will be displayed in the portal. This is the most accurate prediction of when your report will be complete and may differ from the average TAT published on our website. About 85% of our tests will be reported within or before the ERD range. We will notify you of significant delays or holds which will impact the ERD. Learn more about turnaround times here.

Targeted Testing

For ordering sequencing of targeted known variants, go to our Targeted Variants page.


Genetic Counselors


  • Angela Gruber, PhD

Clinical Features and Genetics

Clinical Features

Episodic ataxia type 1 (EA1) is an autosomal dominant K+ channelopathy characterized by short attacks of cerebellar ataxia and dysarthria, and persistent myokymia (Browne et al. 1994; Graves et al. 2014). The first episode of ataxia typically occurs before age 20.

The other KCNA1-associated disease is primary hypomagnesemia, a heterogeneous group of disorders characterized by renal or intestinal magnesium (Mg2+) wasting with resulting tetany, cardiac arrhythmias, and seizures (Glaudemans et al. 2009).


Episodic ataxia type 1 (EA1) is an autosomal dominant disorder caused by defects in the KCNA1 gene (Browne et al. 1994). The KCNA1 gene (one coding exon) encodes the voltage-gated K+ channel Kv1.1, which is abundantly expressed in certain neurons as well as on the apical membrane of cells in the distal convoluted tubule (DCT). Documented genetic defects in KCNA1 associated with episodic ataxia type 1 (EA1) include missense (majority), nonsense, small indels and gross deletion (Human Gene Mutation Database).

To date, only one missense variant (identified with linkage in a large pedigree) in KCNA1 has been associated with isolated autosomal dominant hypomagnesemia (Glaudemans et al. 2009).

Clinical Sensitivity - Sequencing with CNV PG-Select

In a study of 39 unrelated patients with episodic ataxia type 1 (EA1), 10 different pathogenic point variants in KCNA1 were found to account for the genetic basis of 85% of the cohort (Graves et al. 2014).

To date, only one missense variant (identified with linkage in a large pedigree) in KCNA1 has been associated with isolated autosomal dominant hypomagnesemia (Glaudemans et al. 2009).

Only one large deletion involving KCNA1 has been reported (Human Gene Mutation Database). The majority of reported pathogenic variants in KCNA1 are missense variants.

Testing Strategy

This test provides full coverage of the single coding exon of the KCNA1 gene, plus ~10 bases of flanking noncoding DNA. We define full coverage as >20X NGS reads or Sanger sequencing.

Indications for Test

Candidates for this test are patients with episodic ataxia type 1 (EA1) or isolated autosomal dominant hypomagnesemia. Testing is also indicated for family members of patients who have known pathogenic variants in the KCNA1 gene.


Official Gene Symbol OMIM ID
KCNA1 176260
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT


Name Inheritance OMIM ID
Episodic Ataxia Type 1 AD 160120

Related Test

Hypomagnesemia Panel


  • Browne D.L. et al. 1994. Nature Genetics. 8: 136-40. PubMed ID: 7842011
  • Glaudemans B. et al. 2009. The Journal of Clinical Investigation. 119: 936-42. PubMed ID: 19307729
  • Graves T.D. et al. 2014. Brain. 137: 1009-18. PubMed ID: 24578548
  • Human Gene Mutation Database (Bio-base).


Ordering Options

We offer several options when ordering sequencing tests. For more information on these options, see our Ordering Instructions page. To view available options, click on the Order Options button within the test description.

myPrevent - Online Ordering

  • The test can be added to your online orders in the Summary and Pricing section.
  • Once the test has been added log in to myPrevent to fill out an online requisition form.
  • PGnome sequencing panels can be ordered via the myPrevent portal only at this time.

Requisition Form

  • A completed requisition form must accompany all specimens.
  • Billing information along with specimen and shipping instructions are within the requisition form.
  • All testing must be ordered by a qualified healthcare provider.

For Requisition Forms, visit our Forms page

Specimen Types

Specimen Requirements and Shipping Details

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View Ordering Instructions

1) Select Test Method (Platform)

1) Select Test Type

2) Select Additional Test Options

STAT and Prenatal Test Options are not available with Patient Plus.

No Additional Test Options are available for this test.

Note: acceptable specimen types are whole blood and DNA from whole blood only.
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