Long QT Syndrome
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Long QT Syndrome (LQTS) is an inherited heart rhythm disorder characterized by delayed repolarization of the heart after each heartbeat. This delay, visible on an electrocardiogram (ECG) as a prolonged QT interval, creates an electrical instability that can trigger fast, chaotic heartbeats (arrhythmias). These arrhythmias can cause fainting, seizures, or sudden cardiac death, particularly in otherwise healthy young people.
There are multiple types of LQTS, each caused by different genes. LQT1 (KCNQ1 mutations) is often triggered by exercise, especially swimming. LQT2 (KCNH2 mutations) is commonly triggered by emotional stress or sudden loud noises. LQT3 (SCN5A mutations) often causes events during sleep or rest. Other rarer types include those caused by mutations in calmodulin genes (CALM1, CALM2, CALM3) and triadin (TRDN).
Symptoms typically include palpitations, fainting (syncope), and seizures. In some cases, the first symptom may be sudden cardiac arrest. Triggers vary by type but can include exercise, emotional stress, swimming, being startled (like by an alarm), and certain medications. Many people with LQTS have no symptoms and are diagnosed only after a family member is affected or an ECG is done for other reasons.
LQTS is usually inherited in an autosomal dominant pattern, though some forms are autosomal recessive and associated with deafness (Jervell and Lange-Nielsen syndrome). Treatment includes avoiding triggers, beta-blocker medications, and in some cases, implantable cardioverter-defibrillators (ICDs) or left cardiac sympathetic denervation. Knowledge of the specific genetic type helps guide therapy.
NutraHacker examines the following genes related to Long QT Syndrome:
For more information about your own genetic profile as related to Long QT Syndrome, please check out our NutraHacker WGS Critical Genetics Report.
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