What is the role of genetic testing in the workup of long QT syndrome (LQTS)?

Updated: Nov 29, 2017
  • Author: Ali A Sovari, MD, FACP, FACC; Chief Editor: Mikhael F El-Chami, MD  more...
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Answer

Patients with a clinical or electrocardiographic (ECG) presentation of long QT syndrome (LQTS) need genetic testing to identify the mutation. Genetic testing for known mutations in deoxyribonucleic acid (DNA) samples from patients is becoming accessible in specialized centers, although such tests can entail considerable expense, and insurance coverage for genetic testing often requires specific physician intervention.

Identification of an LQTS genetic mutation confirms the diagnosis. However, a negative result on genetic testing is of limited diagnostic value, because only approximately 50% of patients with LQTS have known mutations. The remaining half of patients with LQTS may have mutations of yet unknown genes. Therefore, genetic testing has high specificity but low sensitivity.


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