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HelpTest Code RBART Bartter Syndrome Gene Panel, Varies
Ordering Guidance
The genes associated with Gitelman syndrome (SLC12A3) and autosomal dominant familial hypocalciuric hypercalcemia (FHH, CASR) are not included on this panel. If testing for these disorders and Bartter syndrome on a single panel is desired, order RSCGP / Nephrocalcinosis, Nephrolithiasis, and Renal Electrolyte Imbalance Gene Panel, Varies. It is inappropriate to order both this test and RSCGP on the same patient because the genes on this panel are included on the RSCGP panel.
Targeted testing for familial variants (also called site-specific or known mutations testing) is available for the genes on this panel. See FMTT / Familial Variant, Targeted Testing, Varies. To obtain more information about this testing option, call 800-533-1710.
Customization of this panel and single gene analysis for any gene present on this panel are available. For more information, see CGPH / Custom Gene Panel, Hereditary, Next-Generation Sequencing, Varies. To modify this panel via CGPH, use the Hereditary Renal Conditions disease state for step 1 on the Custom Gene Ordering Tool.
Shipping Instructions
Specimen Required
Patient Preparation A previous hematopoietic stem cell transplant from an allogenic donor will interfere with testing. For information about testing patients who have received a hematopoietic stem cell transplant, call 800-533-1710.
Submit only 1 of the following specimens:
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
3. Whole blood collected postnatal from an umbilical cord is also acceptable. See Additional Information
Specimen Stability Information: Ambient (preferred) 4 days/Refrigerated 4 days/Frozen 4 days
Additional Information:
1. Specimens are preferred to be received within 4 days of collection. Extraction will be attempted for specimens received after 4 days, and DNA yield will be evaluated to determine if testing may proceed.
2. To ensure minimum volume and concentration of DNA are met, the requested volume must be submitted. Testing may be canceled if DNA requirements are inadequate.
3. For postnatal umbilical cord whole blood specimens, maternal cell contamination studies are recommended to ensure test results reflect that of the patient tested. A maternal blood specimen is required to complete maternal cell contamination studies. Order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on both the cord blood and maternal blood specimens under separate order numbers.
Specimen Type: Cultured fibroblasts
Source: Skin or tissue
Container/Tube: T-25 flask
Specimen Volume: 2 Flasks
Collection Instructions: Submit confluent cultured fibroblast cells from a skin or tissue biopsy. Cultured cells from a prenatal specimen will not be accepted.
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours
Additional Information:
1. Specimens are preferred to be received within 24 hours of collection. Culture and extraction will be attempted for specimens received after 24 hours and will be evaluated to determine if testing may proceed.
2. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks are required to culture fibroblasts before genetic testing can occur.
Specimen Type: Extracted DNA
Container/Tube:
Preferred: Screw Cap Micro Tube, 2mL with skirted conical base
Acceptable: Matrix tube, 1 mL
Collection Instructions:
1. The preferred volume is at least 100 mcL at a concentration of 75 ng/mcL.
2. Include concentration and volume on tube.
Specimen Stability Information: Frozen (preferred) 1 year/Ambient/Refrigerated
Additional Information: DNA must be extracted in a CLIA-certified laboratory or equivalent and must be extracted from a specimen type listed as acceptable for this test (including applicable anticoagulants). Our laboratory has experience with Chemagic, Puregene, Autopure, MagnaPure, and EZ1 extraction platforms and cannot guarantee that all extraction methods are compatible with this test. If testing fails, one repeat will be attempted, and if unsuccessful, the test will be reported as failed and a charge will be applied. If applicable, specific gene regions that were unable to be interrogated due to DNA quality will be noted in the report.
Prenatal Specimens
Due to its complexity, consultation with the laboratory is required for all prenatal testing; call 800-533-1710 to speak to a genetic counselor.
Specimen Type: Amniotic fluid
Container/Tube: Amniotic fluid container
Specimen Volume: 20 mL
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours
Additional Information: Specimen will only be tested after culture.
1. Specimens are preferred to be received within 24 hours of collection. Culture and extraction will be attempted for specimens received after 24 hours and will be evaluated to determine if testing may proceed.
2. A separate culture charge will be assessed under CULAF / Culture for Genetic Testing, Amniotic Fluid. An additional 2 to 3 weeks are required to culture amniotic fluid before genetic testing can occur.
3. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Specimen Type: Confluent cultured amniocytes
This does not include cultured chorionic villi.
Container/Tube: T-25 flask
Specimen Volume: 2 Full flasks
Collection Instructions: Submit confluent cultured cells from another laboratory.
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours
Additional Information:
1. Specimens are preferred to be received within 24 hours of collection. Culture and extraction will be attempted for specimens received after 24 hours and will be evaluated to determine if testing may proceed.
2. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing.
3. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Specimen Type: Chorionic villi
Container/Tube: 15-mL tube containing 15 mL of transport media
Specimen Volume: 20 mg
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours
Additional Information: Specimen will only be tested after culture.
1. Specimens are preferred to be received within 24 hours of collection. Culture and extraction will be attempted for specimens received after 24 hours and will be evaluated to determine if testing may proceed.
2. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing. An additional 3 to 4 weeks is required to culture fibroblasts before genetic testing can occur.
3. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Specimen Type: Cultured chorionic villi
Container/Tube: T-25 flasks
Specimen Volume: 2 Full flasks
Collection Instructions: Submit confluent cultured cells from another laboratory
Specimen Stability Information: Ambient (preferred) <24 hours/Refrigerated <24 hours
Additional Information:
1. Specimens are preferred to be received within 24 hours of collection. Culture and extraction will be attempted for specimens received after 24 hours and will be evaluated to determine if testing may proceed.
2. A separate culture charge will be assessed under CULFB / Fibroblast Culture for Biochemical or Molecular Testing.
3. All prenatal specimens must be accompanied by a maternal blood specimen; order MATCC / Maternal Cell Contamination, Molecular Analysis, Varies on the maternal specimen.
Forms
1. New York Clients-Informed consent is required. Document on the request form or electronic order that a copy is on file. The following documents are available:
-Informed Consent for Genetic Testing (T576)
-Informed Consent for Genetic Testing (Spanish) (T826)
2. Hereditary Renal Genetic Testing Patient Information (T918)
3. If not ordering electronically, complete, print, and send a Renal Diagnostics Test Request (T830) with the specimen.
Useful For
Providing a genetic evaluation for patients with a personal or family history suggestive of Bartter syndrome
Establishing a diagnosis of Bartter syndrome
Genetics Test Information
This test utilizes next-generation sequencing to detect single nucleotide, deletion-insertion, and copy number variants in 6 genes associated with Bartter syndrome: BSND, CLCNKA, CLCNKB, KCNJ1, MAGED2, and SLC12A1. See Targeted Genes and Methodology Details for Bartter Syndrome Gene Panel in Method Description for additional details.
Identification of a disease-causing variant may assist with diagnosis, prognosis, clinical management, familial screening, and genetic counseling for Bartter syndrome.
Special Instructions
Method Name
Sequence Capture and Amplicon-Based Next-Generation Sequencing (NGS)
Reporting Name
Bartter Syndrome Gene PanelSpecimen Type
VariesSpecimen Minimum Volume
See Specimen Required
Specimen Stability Information
| Specimen Type | Temperature | Time |
|---|---|---|
| Varies | Varies | |
Reject Due To
All specimens will be evaluated at Mayo Clinic Laboratories for test suitability.Clinical Information
Bartter syndrome (BS) is a rare, hereditary tubulopathy of highly variable severity that can cause renal salt-wasting in infants and young children due to impaired sodium/chloride reabsorption in the thick ascending limb of the nephron.(1)
Characteristic clinical features are hypokalemic, hypochloremic metabolic alkalosis and normal blood pressure despite hyperreninemia and hyperaldosteronism.(1) Children with BS have hypercalciuria and normal serum magnesium levels and may present with symptoms in early childhood or before birth. These symptoms distinguish BS from a more common and milder renal salt-wasting disorder called Gitelman syndrome, which features hypocalciuria and low serum magnesium levels and typically presents after 6 years. Autosomal dominant hypocalcemia may resemble Bartter syndrome in patients with a markedly activating gain-of-function variant but is distinguishable from BS by mode of inheritance and the presence of hypocalcemia and hypomagnesemia.
Age of onset and disease severity is highly variable in Bartter syndrome. The most severe form, antenatal Bartter syndrome (also known as hyperprostaglandin E syndrome or neonatal Bartter syndrome), typically results in polyhydramnios, leading to premature birth. Infants often demonstrate failure to thrive and have significant polyuria resulting in risk for life-threatening salt and water loss.
There are four subtypes of Bartter syndrome that typically present antenatally. BS type 1, caused by biallelic alterations in SLC12A1, may also feature fever, vomiting, and nephrocalcinosis in infancy. BS type 2, caused by biallelic variants in KCNJ1, causes symptoms like BS type 1, but patients may demonstrate transient hyperkalemia and acidosis. BS type 4a, caused by biallelic alterations in BSND, and BS type 4b, caused by alterations in CLCNKA and CLCNKB, may be accompanied by sensorineural deafness in addition to renal salt-wasting and related symptoms. Type 4b is also inherited in an autosomal recessive (or biallelic) pattern or can result from digenic inheritance.
Classic Bartter syndrome, also known as type 3, is the second major form of BS and is caused by alterations in CLCNKB. All BS type 3 patients have marked hypochloremia. Age of onset varies in BS type 3 and may correlate with genotype, with individuals with truncating variants presenting earlier in life. Individuals with BS type 3 may present antenatally with polyhydramnios, during infancy with failure to thrive and lethargy, or in adolescence or adulthood with symptoms of chronic hypokalemia, such as constipation, muscle cramps, salt-craving, nocturia, and vomiting. Nephrocalcinosis is uncommon in BS type 3, and patients are usually normocalciuric but may still have severe electrolyte imbalances.
A third from of BS called transient neonatal Bartter syndrome (BS type 5), is associated with severe polyhydramnios and extreme salt wasting at birth that spontaneously resolves in the first few months of life in surviving patients. BS type 5 is caused by variants in MAGED2 inherited in an X-linked recessive pattern.
Although there is some phenotypic overlap between Bartter syndrome, Gitelman syndrome, and autosomal dominant hypocalcemia, they have different genetic causes.
This panel does not include the genes associated with Gitelman syndrome (SLC12A3) or autosomal dominant hypocalcemia (CASR). If simultaneous genetic testing for Bartter syndrome, Gitelman syndrome and/or autosomal dominant hypocalcemic hypercalciuria is desired, order RSCGP / Nephrocalcinosis, Nephrolithiasis, and Renal Electrolyte Imbalance Gene Panel, Varies.
Reference Values
An interpretive report will be provided.
Interpretation
All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(2) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Day(s) Performed
Varies
Report Available
21 to 35 daysSpecimen Retention Time
Whole blood: 28 days (if available); Extracted DNA: 3 monthsPerforming Laboratory
Mayo Clinic Laboratories in Rochester
Test Classification
This test was developed and its performance characteristics determined by Mayo Clinic in a manner consistent with CLIA requirements. It has not been cleared or approved by the US Food and Drug Administration.CPT Code Information
81404
81406
81407
81479
81479 (if appropriate for government payers)
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| RBART | Bartter Syndrome Gene Panel | 51966-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 618101 | Test Description | 62364-5 |
| 618102 | Specimen | 31208-2 |
| 618103 | Source | 31208-2 |
| 618104 | Result Summary | 50397-9 |
| 618105 | Result | 82939-0 |
| 618106 | Interpretation | 69047-9 |
| 618107 | Additional Results | 82939-0 |
| 618108 | Resources | 99622-3 |
| 618109 | Additional Information | 48767-8 |
| 618110 | Method | 85069-3 |
| 618111 | Genes Analyzed | 48018-6 |
| 618112 | Disclaimer | 62364-5 |
| 618113 | Released By | 18771-6 |
Reflex Tests
| Test ID | Reporting Name | Available Separately | Always Performed |
|---|---|---|---|
| CULFB | Fibroblast Culture for Genetic Test | Yes | No |
| CULAF | Amniotic Fluid Culture/Genetic Test | Yes | No |
| MATCC | Maternal Cell Contamination, B | Yes | No |
Testing Algorithm
Prenatal specimens:
If an amniotic fluid specimen or cultured amniocytes are received, an amniotic fluid culture will be performed at an additional charge.
If a chorionic villi specimen or cultured chorionic villi are received, a fibroblast culture will be performed at an additional charge.
For any prenatal specimen that is received, maternal cell contamination testing will be performed at an additional charge.
Skin biopsy or cultured fibroblast specimens:
For skin biopsy or cultured fibroblast specimens, a fibroblast culture will be performed at an additional charge. If viable cells are not obtained, the client will be notified.
Cord blood:
For cord blood specimens that have an accompanying maternal blood specimen, maternal cell contamination studies will be performed at an additional charge.