Genetic Testing for Long QT Syndrome (LQTS)

Long QT Syndrome (LQTS) is a hereditary ion channel disorder that can lead to dangerous ventricular arrhythmias, syncope, or sudden cardiac death. The condition often manifests before the age of 40, and 10–15% of patients may experience sudden death.

Genetic testing plays a diagnostic, prognostic, and therapeutic role, helping to identify pathogenic variants, guide treatment strategies, and manage at-risk family members.

GENOSOPHY®’s LQTS Genetic Panel includes 18 genes associated with inherited delays in cardiac repolarization. It is aligned with the guidelines of all major international cardiology organizations, including the American College of Cardiology (ACC), American Heart Association (AHA), European Society of Cardiology (ESC), Heart Failure Society of America (HFSA), and Heart Rhythm Society (HRS).

Conditions Covered by GENOSOPHY®’s LQTS Genetic Panel

• Romano-Ward Syndrome – Classic LQTS without hearing loss
• Jervell and Lange-Nielsen Syndrome (JLNS) – LQTS with congenital deafness
• Timothy Syndrome – LQTS with co-occurring neurodevelopmental disorders
• Other genetic arrhythmopathies associated with QT prolongation

Clinical Benefits

Diagnosis

• Confirmation of the genetic cause in patients with prolonged QT
• Improved differential diagnosis between LQTS and other arrhythmogenic conditions

Prognosis

• Assessment of sudden cardiac death risk
• Definition of preventive strategies for at-risk relatives

Management

• Pharmacogenetic guidance – Avoidance of QT-prolonging medications
• ICD implantation decisions in patients at high risk of ventricular arrhythmias
• Family screening and implementation of preventive strategies

Testing Procedure

1. Blood or saliva sample collection
2. Analysis of 18 genes associated with LQTS using Next Generation Sequencing (NGS)
3. Results available within ~5 weeks

Genetic counseling and expert interpretation of results is available as an additional service by faculty members of the National and Kapodistrian University of Athens (NKUA).

Genes Included in the Genetic Panel

AKAP9, ANK2, CACNA1C*, CALM1*, CALM2, CALM3, CAV3, KCNE1, KCNE2, KCNH2, KCNJ2, KCNJ5, KCNQ1, NOS1AP, SCN5A, SLC12A3, TECRL, TRDN

Note: In addition to full exon sequencing, GENOSOPHY® also analyzes dozens of non-coding variants, such as those in promoters and introns. Detection sensitivity for SNVs, indels, and CNVs is >99%. Sensitivity may be slightly lower for genes marked with an asterisk (*).