Jervell and Lange-Nielsen syndrome
Early therapy with implanted cardioverter/defibrillators (ICDs) must be considered in high-risk cases of congenital Long QT syndrome (LQTS). ⚡
📖 About
- Inherited cause of Long QT syndrome (LQTS).
- Particularly associated with the Jervell and Lange-Nielsen syndrome, which combines congenital deafness with prolonged QT interval.
- Inheritance is typically autosomal recessive for this severe form, while other LQTS variants can be autosomal dominant (Romano-Ward syndrome).
🧬 Aetiology
- Caused by mutations in the KCNQ1 and KCNE1 genes.
- These genes encode subunits of a potassium channel that helps repolarize cardiac cells after depolarization.
- Potassium ion movement is also important in the inner ear → explains the sensorineural deafness often associated.
- Defective ion channels → delayed repolarisation → prolonged QT interval → risk of arrhythmias.
🩺 Clinical Features
- May be asymptomatic until a trigger.
- Arrhythmias: Syncope, torsades de pointes, ventricular tachycardia.
- Triggers: Emotional stress, exercise (particularly swimming), or sudden fright.
- Sensorineural deafness: Seen in Jervell and Lange-Nielsen variant.
- Sudden cardiac death (SCD): Often first presentation in undiagnosed cases.
🔍 Differentials
- Other inherited arrhythmia syndromes (Brugada, catecholaminergic polymorphic VT).
- Drug-induced QT prolongation (antiarrhythmics, macrolides, fluoroquinolones, antipsychotics).
- Electrolyte disturbances (hypokalaemia, hypocalcaemia, hypomagnesaemia).
🧪 Investigations
- ECG: Prolonged QT interval, torsades de pointes episodes.
- Holter monitoring: Detects intermittent arrhythmias.
- Genetic testing: Confirms mutations in KCNQ1/KCNE1.
- Audiometry: Assesses associated congenital deafness.
💊 Management
- β-blockers: First-line (e.g., propranolol, nadolol), but limited efficacy in Jervell and Lange-Nielsen type.
- ICD (Implantable Cardioverter-Defibrillator): Recommended in high-risk patients or survivors of cardiac arrest.
- Lifestyle modification: Avoid QT-prolonging drugs, correct electrolytes, restrict strenuous exercise/swimming.
- Potassium supplementation: May help reduce arrhythmic risk in some patients.
- Family screening: ECG + genetic testing of relatives is essential.
📚 References
🧾 Clinical Case Example – Jervell & Lange-Nielsen Syndrome
A 9-year-old girl is brought to clinic after a syncopal episode while running at school.
Her parents report she has had congenital profound sensorineural deafness since infancy and uses a hearing aid.
On examination, she is well with normal heart sounds.
ECG shows a markedly prolonged QT interval (>500 ms).
There is a strong family history of sudden unexplained death in childhood.
👉 Diagnosis: Jervell and Lange-Nielsen syndrome (autosomal recessive long QT with congenital deafness).
👉 Management: β-blockers (e.g. propranolol), avoidance of QT-prolonging drugs, and ICD if high-risk.
Family members should undergo genetic counselling and screening.
