Long QT Syndrome NGS Panel

Test Information

This panel of 18 genes intended for patients with a diagnosis or clinical suspicion of Long QT Syndrome and is performed by Next Generation Sequencing (NGS).

Turnaround Time

8 weeks

CPT Code(s)





  • AKAP9
  • ANK2
  • CALM1
  • CALM2
  • CASQ2
  • CAV3
  • KCNE1
  • KCNE2
  • KCNH2
  • KCNJ2
  • KCNJ5
  • KCNQ1
  • RYR2
  • SCN4B
  • SCN5A
  • SNTA1
  • TRDN

Clinical Information

Long QT syndrome refers to a category of cardiac arrhythmias involving a prolonged QT interval that can be detected by EKG. Affected individuals may experience fainting episodes and ventricular tachycardia (specifically torsade de pointes), and in some cases, sudden death may occur. Exercise, stress, and loud noises have been implicated as precursers to cardiac events in certain types of Long QT syndrome. Hearing loss is an additional feature in individuals with Jervell and Lange-Nielsen syndrome. Long QT syndrome is usually inherited in an autosomal dominant pattern with reduced penetrance, but the risk of significant episodes may decrease after early adulthood. This panel consists of 18 genes that are associated with this condition.


Next Generation Sequencing


The current design of this panel covers all genes and the flanking intronic sequences. This method allows for analysis of greater than 98% of the targeted sequence for the detection of nucleotide substitutions and small deletions and duplications. Large deletions and duplications will not be detected by this panel. Mutations and variants identified on the panel are confirmed with Sanger sequencing. All novel and apparently pathogenic changes are reported when found within the coding region as well as within 10 basepairs of each intron/exon boundary for each gene. Promoter and 3' untranslated sequences are not included in the current analysis. It should be noted that the current protocol is not specifically designed to detect copy number alterations and single exon deletions may require additional follow-up to determine whether or not they represent technical artifacts. We recommend further array-based testing to more accurately address the concerns of dosage alterations. The Cytogenetic Laboratory at GGC offers a high resolution whole genome SNP microarray. The GGC Diagnostic Laboratory Directors are available for further consultation regarding the limitations of the NGS and array testing procedures.

Specimen Requirements

The preferred sample type is 3-5 ml of peripheral blood collected in an EDTA (purple top) tube. Extracted DNA and saliva are also accepted for this test. Saliva samples must be submitted in an approved saliva kit. Contact the lab to receive a saliva kit or to have one sent to your patient.

Transport Instructions

The specimen should be kept at room temperature and delivered via overnight shipping. If shipment is delayed by one or two days, the specimen should be refrigerated and shipped at room temperature. Do not freeze the specimen. Samples collected on Friday can be safely designated for Monday delivery.

Prenatal Testing Information

If the pathogenic mutation(s) are identified in an affected individual using this panel, prenatal diagnosis is available for future pregnancies. Sanger sequencing will be used for prenatal diagnosis when there is a known familial mutation. Additional fees for cell culture and maternal cell contamination may apply. Maternal cell contamination studies are required for all prenatal molecular tests. Contact the laboratory prior to sending a prenatal specimen.

Have Questions? Need Support?

Call our laboratory at 1-800-473-9411 or contact one of our Laboratory Genetic Counselors for assistance.
Robin Fletcher, MS, CGC
Falecia Thomas, MS, CGC
Alex Finley, MS, CGC

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