Bartter Syndrome Type 2 via the KCNJ1 Gene

Summary and Pricing

Test Method

Exome Sequencing with CNV Detection
Test Code Test Copy GenesTest CPT Code Gene CPT Codes Copy CPT Codes Base Price
8723 KCNJ1 81404 81404,81479 $890 Order Options and Pricing
Test Code Test Copy Genes Test CPT Code Gene CPT Codes Copy CPT Code Base Price
8723KCNJ181404 81404, 81479 $890 Order Options and Pricing

Pricing Comments

Our favored testing approach is exome based NextGen sequencing with CNV analysis. This will allow cost effective reflexing to PGxome or other exome based tests. However, if full gene Sanger sequencing is desired for STAT turnaround time, insurance, or other reasons, please see link below for Test Code, pricing, and turnaround time information. If the Sanger option is selected, CNV detection may be ordered through Test #600.

A 25% additional charge will be applied to STAT orders. View STAT turnaround times here.

For Reflex to PGxome pricing click here.

The Sanger Sequencing method for this test is NY State approved.

For Sanger Sequencing click here.

Targeted Testing

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

Turnaround Time

18 days on average

EMAIL CONTACTS

Genetic Counselors

Geneticist

Clinical Features and Genetics

Clinical Features

Bartter syndrome is a group of genetically heterogeneous renal tubular disorders characterized by renal hypokalaemia, metabolic alkalosis and secondary hyperaldosteronism with normal to low blood pressure due to a renal loss of sodium (Simon et al. 1996; Scheinman et al. 1999; Brochard et al. 2009). Bartter syndrome type 2 is an antenatal condition caused by loss-of-function mutations in the potassium channel Kir 1.1 (or ROMK) encoded by the KCNJ1 gene. Common clinical features include hypercalciuria with nephrocalcinosis, maternal polyhydramnios leading to premature birth, intrauterine and postnatal polyuria, recurrent vomiting, failure to thrive and growth retardation. The presence of early transitory hyperkalaemia suggests defects in KCNJ1.

Genetics

Bartter syndrome type 2 is an autosomal recessive disorder caused by defects in the KCNJ1 gene (Simon et al. 1996). KCNJ1 has two coding exons that encode the potassium channel Kir 1.1 (or ROMK), which plays an important role in potassium homeostasis. Genetic defects of KCNJ1 occur throughout the whole coding region and include missense, nonsense mutations and small deletion/insertions (Human Gene Mutation Database). Exon-level large deletions involving KCNJ1 have been also reported, but are uncommon.

Testing Strategy

This test provides full coverage of all coding exons of the KCNJ1 gene plus 10 bases of flanking noncoding DNA in all available transcripts along with other non-coding regions in which pathogenic variants have been identified at PreventionGenetics or reported elsewhere. We define full coverage as >20X NGS reads or Sanger sequencing.

Since this test is performed using exome capture probes, a reflex to any of our exome based tests is available (PGxome, PGxome Custom Panels).

Clinical Sensitivity - Sequencing with CNV PGxome

Detection rates of pathogenic variants in the KCNJ1 gene in a large cohort of patients with Bartter syndrome type 2 are unknown in the literature because documented KCNJ1 pathogenic variants have only been reported in limited cases.

Indications for Test

Candidates for this test are patients with Bartter syndrome type 2. Testing is also indicated for family members of patients who have known KCNJ1 mutations. This test may also be considered for the reproductive partners of individuals who carry pathogenic variants in KCNJ1.

Gene

Official Gene Symbol OMIM ID
KCNJ1 600359
Inheritance Abbreviation
Autosomal Dominant AD
Autosomal Recessive AR
X-Linked XL
Mitochondrial MT

Disease

Name Inheritance OMIM ID
Bartter Syndrome Antenatal Type 2 AR 241200

Related Test

Name
Nephrolithiasis and Nephrocalcinosis Panel

Citations

  • Brochard K, Boyer O, Blanchard A, Loirat C, Niaudet P, Macher M-A, Deschenes G, Bensman A, Decramer S, Cochat P, Morin D, Broux F, et al. 2009. Phenotype-genotype correlation in antenatal and neonatal variants of Bartter syndrome. Nephrol. Dial. Transplant. 24: 1455–1464. PubMed ID: 19096086
  • Human Gene Mutation Database (Bio-base).
  • Scheinman SJ, Guay-Woodford LM, Thakker RV, Warnock DG. 1999. Genetic disorders of renal electrolyte transport. N. Engl. J. Med. 340: 1177–1187. PubMed ID: 10202170
  • Simon DB, Karet FE, Rodriguez-Soriano J, Hamdan JH, DiPietro A, Trachtman H, Sanjad SA, Lifton RP. 1996. Genetic heterogeneity of Bartter’s syndrome revealed by mutations in the K+ channel, ROMK. Nat. Genet. 14: 152–156. PubMed ID: 8841184

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.

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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ORDER OPTIONS

View Ordering Instructions

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.

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