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 Genes | Test CPT Code | Gene CPT Codes Copy CPT Code | Base Price | |
|---|---|---|---|---|---|
| 9249 | KCNA1 | 81479 | 81479,81479 | $990 | Order Options and Pricing |
Pricing Comments
Testing run on PG-select capture probes includes CNV analysis for the gene(s) on the panel but does not permit the optional add on of exome-wide CNV analysis. Any of the NGS platforms allow reflex to other clinically relevant genes, up to whole exome or whole genome sequencing depending upon the base platform selected for the initial test.
An additional 25% charge will be applied to STAT orders. STAT orders are prioritized throughout the testing process.
This test is also offered via a custom panel (click here) on our exome or genome backbone which permits the optional add on of exome-wide CNV or genome-wide SV analysis.
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.
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).
Genetics
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.
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.
Gene
| Official Gene Symbol | OMIM ID |
|---|---|
| KCNA1 | 176260 |
| Inheritance | Abbreviation |
|---|---|
| Autosomal Dominant | AD |
| Autosomal Recessive | AR |
| X-Linked | XL |
| Mitochondrial | MT |
Disease
| Name | Inheritance | OMIM ID |
|---|---|---|
| Episodic Ataxia Type 1 | AD | 160120 |
Related Test
| Name |
|---|
| Hypomagnesemia Panel |
Citations
Ordering/Specimens
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
If ordering a Duo or Trio test, the proband and all comparator samples are required to initiate testing. If we do not receive all required samples for the test ordered within 21 days, we will convert the order to the most effective testing strategy with the samples available. Prior authorization and/or billing in place may be impacted by a change in test code.
Specimen Types
Specimen Requirements and Shipping Details
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ORDER OPTIONS
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2) Select Additional Test Options
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