LongQTNext is an analysis of 17 genes associated with inherited arrhythmias. RhythmNext is a comprehensive analysis of 42 genes associated with inherited arrhythmias. Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized kit and quantified. Sequence enrichment of the targeted coding exons and adjacent intronic nucleotides is carried out by a bait-capture methodology using long biotinylated oligonucleotide probes, and is followed by polymerase chain reaction (PCR) and Next-Generation sequencing. Additional Sanger sequencing is performed for any regions missing or with insufficient read depth coverage for reliable heterozygous variant detection. Potentially homozygous variants, variants in regions complicated by pseudogene interference, and variant calls not satisfying depth of coverage and variant allele frequency quality thresholds are verified by Sanger sequencing. This assay targets all coding domains, and well into the flanking 5’ and 3’ ends of all the introns and untranslated regions. Gross deletion/duplication analysis is performed for all genes using a custom pipeline based on read-depth from NGS data followed by a confirmatory orthogonal method, as needed. Exon-level resolution may not be achieved for every gene.
Genetic Testing for Long QT | Inherited Arrhythmia | LongQTNext & RhythmNext
Genes analyzed
Why Is This Important?
Knowing if your patient has a hereditary cardiovascular disorder can help you determine their future cardiovascular disease risks and guide your medical management recommendations. Key benefits include:
- Clarify diagnosis and risk for sudden cardiac arrest
- Target cardiac event triggers, cardiac event incidence, and management plan to an individual’s genotype
- Adjust management in those with LQTS due to conditions like Jervell and Lange-Nielsen and Andersen-Tawil syndromes
- May identify the cause of a sudden unexplained death after a normal autopsy
- Offer family members genetic testing (for a familial mutation) and implement medical surveillance to only those that need it
- Reduce healthcare costs, resources, and anxiety for families
When To Consider Testing
- Patient has a strong clinical suspicion for LQTS, based on clinical and family history and prolonged QT interval on EKG defined as QTc>480 ms (adolescents) or >500 ms (adults)*
- Patient is asymptomatic with QT prolongation in the absence of other clinical explanations*
- Patient has a strong clinical suspicion for BrS or SQTS, based on clinical/family history and EKG patter
- Patient has a personal or family history of unexplained sudden cardiac arrest/death, with structurally normal heart and normal physical exam/autopsy
*Recommendations from 2011 Heart Rhythm Society (HRS) and European Heart Rhythm Association (EHRA) Expert Consensus Statement
Mutation Distribution and Detection Rates
Test Description
LongQTNext is an analysis of 17 genes associated with inherited arrhythmias. RhythmNext is a comprehensive analysis of 42 genes associated with inherited arrhythmias. Genomic deoxyribonucleic acid (gDNA) is isolated from the patient’s specimen using a standardized kit and quantified. Sequence enrichment of the targeted coding exons and adjacent intronic nucleotides is carried out by a bait-capture methodology using long biotinylated oligonucleotide probes, and is followed by polymerase chain reaction (PCR) and Next-Generation sequencing. Additional Sanger sequencing is performed for any regions missing or with insufficient read depth coverage for reliable heterozygous variant detection. Potentially homozygous variants, variants in regions complicated by pseudogene interference, and variant calls not satisfying depth of coverage and variant allele frequency quality thresholds are verified by Sanger sequencing. This assay targets all coding domains, and well into the flanking 5’ and 3’ ends of all the introns and untranslated regions. Gross deletion/duplication analysis is performed using a custom pipeline based on read-depth from NGS data followed by a confirmatory orthogonal method, as needed. Exon-level resolution may not be achieved for every gene.
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