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Long QT Syndrome
Long QT syndrome basic panel [11 genes]: this panel includes the genes where most mutations with clinically proven association responsible for long QT syndrome are identified.
| CACNA1C | CALM1 | CALM2 | CALM3 | KCNE1 | KCNE2 | KCNH2 | KCNJ2 | KCNQ1 | SCN5A |
| RYR2 |
Long QT syndrome extended panel [32 genes]: this panel includes priority genes that are most frequently associated with the development of long QT syndrome. It also includes secondary genes associated with this entity, although with a lower level of evidence, as well as candidate genes of which only functional evidence of association exists.
It is indicated in those cases where an unequivocal clinical diagnosis of long QT syndrome exists and no mutations were identified by the 8-gene panel. This allows identifying variants potentially associated with the phenotype in those genes where the responsible mutations are less prevalent.
It should be considered as a first approach when an exhaustive genetic study of this pathology is intended, since this is the most complete panel on the market. The extended study can also be useful in families under suspicion of complex genotypes, with an important variability in phenotypic expression among its members.
| CACNA1C | CALM1 | CALM2 | CALM3 | KCNE1 | KCNE2 | KCNH2 | KCNJ2 | KCNQ1 | SCN5A |
| AKAP9 | ANK2 | CAV3 | KCNJ5 | RYR2 | SCN4B | SLC22A5 | SNTA1 | TECRL | TRDN |
| CAVIN1 | FHL2* | HCN4* | KCNA5* | KCND2* | KCND3* | KCNE3* | KCNE5* | NOS1AP* | SCN1B* |
| SCN3B* | TRPM4* |
Arrhythmias and Sudden Death without Structural Cardiopathy General Panel [90 genes]: this panel is mainly oriented at diagnosing of phenotypes that present ventricular arrhythmias as a primary manifestation of the disease without apparent structural heart disease and not clearly defined phenotype.
It is intended for those individuals whose clinical or anatomopathological study does not show structural alterations, and would be the testing of choice in cases of sudden death with negative autopsy. It should be especially considered in patients with personal or family history of sudden death, subjects with a history of syncope of undetermined origin, or individuals with idiopathic ventricular fibrillation without structural heart disease.
Cardiomyopathies, Arrhythmias, and Sudden Death General Panel [251 genes]: this panel is mainly aimed at the diagnosis of cases where it is not possible to establish a clearly defined phenotype, but where cardiac arrhythmias are the main manifestation.
It is mainly intended for subjects with personal or familial history of sudden death with unknown origin or subjects with ventricular fibrillation of unknown origin that meet the above-mentioned characteristics.
Cardiovascular Diseases General Panel [405 genes]: this panel includes all genes associated or potentially associated with the development of inherited cardiovascular diseases as well as genes associated with increased global/general cardiovascular risk.
It covers a group of heterogeneous diseases, and genetic testing allows for the differential diagnosis between them. It is also useful when a multigenic etiology is suspected. It should be considered when an exhaustive study of all genes related to cardiovascular pathologies is intended, especially in cases of sudden death where clinical or pathological information is incomplete or the diagnosis is unclear.
As for research, it is an attractive alternative to the exomes because it includes both genes with proven pathogenicity and candidate genes. The study ensures maximum yield with adequate coverages (which allows for assessing structural variants, such as large deletions and duplications).
This panel includes the genes where most mutations with clinically proven association responsible for long QT syndrome are identified.
| CACNA1C | CALM1 | CALM2 | CALM3 |
| KCNE1 | KCNE2 | KCNH2 | KCNJ2 |
| KCNQ1 | SCN5A | RYR2 |
This panel includes priority genes that are most frequently associated with the development of long QT syndrome. It also includes secondary genes associated with this entity, although with a lower level of evidence, as well as candidate genes of which only functional evidence of association exists.
It is indicated in those cases where an unequivocal clinical diagnosis of long QT syndrome exists and no mutations were identified by the 8-gene panel. This allows identifying variants potentially associated with the phenotype in those genes where the responsible mutations are less prevalent.
It should be considered as a first approach when an exhaustive genetic study of this pathology is intended, since this is the most complete panel on the market. The extended study can also be useful in families under suspicion of complex genotypes, with an important variability in phenotypic expression among its members.
| CACNA1C | CALM1 | CALM2 | CALM3 |
| KCNE1 | KCNE2 | KCNH2 | KCNJ2 |
| KCNQ1 | SCN5A | AKAP9 | ANK2 |
| CAV3 | KCNJ5 | RYR2 | SCN4B |
| SLC22A5 | SNTA1 | TECRL | TRDN |
| CAVIN1 | FHL2* | HCN4* | KCNA5* |
| KCND2* | KCND3* | KCNE3* | KCNE5* |
| NOS1AP* | SCN1B* | SCN3B* | TRPM4* |
This panel is mainly oriented at diagnosing of phenotypes that present ventricular arrhythmias as a primary manifestation of the disease without apparent structural heart disease and not clearly defined phenotype.
It is intended for those individuals whose clinical or anatomopathological study does not show structural alterations, and would be the testing of choice in cases of sudden death with negative autopsy. It should be especially considered in patients with personal or family history of sudden death, subjects with a history of syncope of undetermined origin, or individuals with idiopathic ventricular fibrillation without structural heart disease.
This panel is mainly aimed at the diagnosis of cases where it is not possible to establish a clearly defined phenotype, but where cardiac arrhythmias are the main manifestation.
It is mainly intended for subjects with personal or familial history of sudden death with unknown origin or subjects with ventricular fibrillation of unknown origin that meet the above-mentioned characteristics.
This panel includes all genes associated or potentially associated with the development of inherited cardiovascular diseases as well as genes associated with increased global/general cardiovascular risk.
It covers a group of heterogeneous diseases, and genetic testing allows for the differential diagnosis between them. It is also useful when a multigenic etiology is suspected. It should be considered when an exhaustive study of all genes related to cardiovascular pathologies is intended, especially in cases of sudden death where clinical or pathological information is incomplete or the diagnosis is unclear.
As for research, it is an attractive alternative to the exomes because it includes both genes with proven pathogenicity and candidate genes. The study ensures maximum yield with adequate coverages (which allows for assessing structural variants, such as large deletions and duplications).
- Patients with diagnosed long QT syndrome (Schwartz score >3 or QTc >500 ms).
- Patients under clinical suspicion of long QT syndrome:
- Asymptomatic subjects with serial ECGs showing QTc values >460 ms (prepubescent) or >480 ms (adults).
- Subjects with a personal or family history of sudden death.
- Subjects with a history of syncope of unknown origin.
- Subjects with ventricular fibrillation of unknown origin.
- Relatives of patients with genetic diagnosis of long QT syndrome.
- HRS/EHRA/APHRS expert consensus statement on the diagnosis and management of patients with inherited primary arrhythmia syndromes: document endorsed by HRS, EHRA, and APHRS in May 2013 and by ACCF, AHA, PACES, and AEPC in June 2013. Priori SG et al. Heart Rhythm. 2013 Dec;10(12):1932-63.
- HRS/EHRA expert consensus statement on the state of genetic testing for the channelopathies and cardiomyopathies: this document was developed as a partnership between the Heart Rhythm Society (HRS) and the European Heart Rhythm Association (EHRA). Ackerman MJ, Priori SG, et al. Europace. 2011 Aug;13(8):1077-109
- Recommendations for the use of genetic testing in the clinical evaluation of inherited cardiac arrhythmias associated with sudden cardiac death: Canadian Cardiovascular Society/Canadian Heart Rhythm Society joint position paper. Gollob MH et al., Can J Cardiol. 2011 Mar-Apr;27(2):232-45.
- Clinical utility gene card for: long-QT syndrome (types 1-13). Beckmann BM1, Wilde AA, Kääb S. et al. Eur J Hum Genet. 2013 Oct;21(10).
- Genetic testing for long QT syndrome and the category of cardiac ion channelopathies. Modell SM, Bradley DJ, Lehmann MH. PLoS Curr. 2012 May 3.
The yield of genetic testing in correctly characterized subjects is approximately 75%-80%. The clinical specificity of the test is close to 95%. The positive clinical predictive value (possibility of carriers developing the disease throughout their life) depends on the identified variant, with an average of 60%. Around 5% of cases can be carriers of more than one variant in the same or different genes.
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