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HelpTest ID: SQTSG Short QT Syndrome Gene Panel, Varies
Ordering Guidance
This test is intended for genetic screening for and diagnosis of short QT syndrome.
For comprehensive inherited cardiac arrhythmia genetic testing, order CARGG / Comprehensive Arrhythmia Gene Panel, Varies.
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.
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.
Shipping Instructions
Specimen preferred to arrive within 96 hours of collection.
Necessary Information
Prior Authorization is available, but not required, for this test. If proceeding with the prior authorization process, submit the required form with the specimen.
Specimen Required
Patient Preparation: A previous bone marrow transplant from an allogenic donor will interfere with testing. Call 800-533-1710 for instructions for testing patients who have received a bone marrow transplant.
Specimen Type: Whole blood
Container/Tube:
Preferred: Lavender top (EDTA) or yellow top (ACD)
Acceptable: Any anticoagulant
Specimen Volume: 3 mL
Collection Instructions:
1. Invert several times to mix blood.
2. Send whole blood specimen in original tube. Do not aliquot.
Specimen Stability Information: Ambient (preferred)/Refrigerated
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 Cardiomyopathies and Arrhythmias Patient Information (T725)
3. Short QT Syndrome Gene Panel (SQTSG) Prior Authorization Ordering Instructions
4. If not ordering electronically, complete, print, and send a Cardiovascular Test Request (T724) with the specimen.
Useful For
Providing a genetic evaluation for patients with a personal or family history suggestive of short QT syndrome
Establishing a diagnosis of short QT syndrome
Special Instructions
Method Name
Sequence Capture and Targeted Next-Generation Sequencing followed by Polymerase Chain Reaction (PCR) and Sanger Sequencing
Reporting Name
Short QT Syndrome Gene PanelSpecimen Type
VariesSpecimen Minimum Volume
1 mL
Specimen Stability Information
| Specimen Type | Temperature | Time | Special Container |
|---|---|---|---|
| Varies | Varies | ||
Clinical Information
Short QT syndrome (SQTS) is a genetic cardiac arrhythmia condition characterized by a shortened QT interval and T-wave abnormalities on electrocardiogram (ECG).(1) SQTS may result in or present with recurrent syncope, ventricular arrhythmia, sudden cardiac arrest, and sudden cardiac death.(1)
The prevalence of SQTS is unknown, but the condition is thought to be rare.(2) The overall diagnostic yield of genetic testing for SQTS is estimated to be 5% to 20%.(2,3) While disease-causing variants in several genes have been reported in association with SQTS, the strongest evidence of association is currently limited to gain-of- function variants in the cardiac ion change genes KCNH2, KCNJ2, and KCNQ1,(4) and loss-of-function variants in the SLC4A3 gene.(5) Based on current knowledge, SQTS follows an autosomal dominant pattern of inheritance.
Genetic testing in SQTS is recommended to confirm the clinical diagnosis, assist with risk stratification, guide management, and identify at-risk family members. Even individuals with a normal QT interval may still be at risk for a cardiac event and sudden cardiac death; thus, ECG analysis alone is insufficient to rule out the diagnosis, and genetic testing is necessary to confirm the presence or absence of disease in at-risk family members.(1-5)
Reference Values
An interpretive report will be provided.
Interpretation
All detected variants are evaluated according to American College of Medical Genetics and Genomics recommendations.(6) Variants are classified based on known, predicted, or possible pathogenicity and reported with interpretive comments detailing their potential or known significance.
Clinical Reference
1. Campuzano O, Fernandez-Falgueras A, Lemus X, et al: Short QT syndrome: A comprehensive genetic interpretation and clinical translation of rare variants. J Clin Med. 2019 Jul 16;8(7):1035. doi:10.3390/jcm8071035
2. Mazzanti A, Underwood K, Nevelev D, Kofman S, Priori SG: The new kids on the block of arrhythmogenic disorders: Short QT syndrome and early repolarization. J Cardiovasc Electrophysiol. 2017 Oct;28(10):1226-1236. doi: 10.1111/jce.13265
3. Priori SG, Blomstrom-Lundqvist C, Mazzanti A, et al; ESC Scientific Document Group: 2015 ESC Guidelines for the management of patients with ventricular arrhythmias and the prevention of sudden cardiac death: The Task Force for the Management of Patients with Ventricular Arrhythmias and the Prevention of Sudden Cardiac Death of the European Society of Cardiology (ESC). Endorsed by: Association for European Paediatric and Congenital Cardiology (AEPC). Eur Heart J. 2015 Nov 1;36(41):2793-2867. doi: 10.1093/eurheartj/ehv316
4. Walsh R, Adler A, Amin AS, et al: Evaluation of gene validity for CPVT and short QT syndrome in sudden arrhythmic death. Eur Heart J. 2022 Apr 14:43(15):1500-1510. doi: 10.1093/eurheartj/ehab687
5. Thorsen K, Dam VS, Kjaer-Sorensen K, et al: Loss-of-activity-mutation in the cardiac chloride-bicarbonate exchanger AE3 causes short QT syndrome. Nat Commun. 2017 Nov 22;8(1):1696. doi: 10.1038/s41467-017-01630-0
6. Richards S, Aziz N, Bale S, et al: Standards and guidelines for the interpretation of sequence variants: a joint consensus recommendation of the American College of Medical Genetics and Genomics and the Association for Molecular Pathology. Genet Med. 2015 May;17(5):405-424
Day(s) Performed
Varies
Report Available
28 to 42 daysTest 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
81403
81406 x 2
81479
LOINC Code Information
| Test ID | Test Order Name | Order LOINC Value |
|---|---|---|
| SQTSG | Short QT Syndrome Gene Panel | 51966-0 |
| Result ID | Test Result Name | Result LOINC Value |
|---|---|---|
| 617464 | Test Description | 62364-5 |
| 617465 | Specimen | 31208-2 |
| 617466 | Source | 31208-2 |
| 617467 | Result Summary | 50397-9 |
| 617468 | Result | 82939-0 |
| 617469 | Interpretation | 69047-9 |
| 617470 | Additional Results | 82939-0 |
| 617471 | Resources | 99622-3 |
| 617472 | Additional Information | 48767-8 |
| 617473 | Method | 85069-3 |
| 617474 | Genes Analyzed | 48018-6 |
| 617475 | Disclaimer | 62364-5 |
| 617476 | Released By | 18771-6 |
multi-gene panel