GTR Home > Conditions/Phenotypes > Long QT syndrome 2

Summary

Excerpted from the GeneReview: Long QT Syndrome
Long QT syndrome (LQTS) is a cardiac electrophysiologic disorder, characterized by QT prolongation and T-wave abnormalities on the ECG and the ventricular tachycardia torsade de pointes (TdP). TdP is usually self-terminating, thus causing a syncopal event, the most common symptom in individuals with LQTS. Syncope typically occurs during exercise and high emotions, less frequently at rest or during sleep, and usually without warning. In some instances, TdP degenerates to ventricular fibrillation and causes aborted cardiac arrest (if the individual is defibrillated) or sudden death. Approximately 50% of individuals with a pathogenic variant in one of the genes associated with LQTS have symptoms, usually one to a few syncopal spells. While cardiac events may occur from infancy through middle age, they are most common from the pre-teen years through the 20s. Some types of LQTS are associated with a phenotype extending beyond cardiac arrhythmia. In addition to the prolonged QT interval, associations include muscle weakness and facial dysmorphism in Andersen-Tawil syndrome (LQTS type 7), hand/foot, facial, and neurodevelopmental features in Timothy syndrome (LQTS type 8) and profound sensorineural hearing loss in Jervell and Lange-Nielson syndrome.

Available tests

57 tests are in the database for this condition.

Check Associated genes and Related conditions for additional relevant tests.

Associated genes

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Clinical features

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Practice guidelines

  • ACMG, 2015
    ACMG policy statement: updated recommendations regarding analysis and reporting of secondary findings in clinical genome-scale sequencing.
  • ACMG, 2013
    ACMG recommendations for reporting of incidental findings in clinical exome and genome sequencing.

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