Jervell and Lange-Nielsen syndrome

Overview

Jervell and Lange-Nielsen syndrome (JLNS) is a rare inherited disorder that affects the electrical system of the heart and the inner ear. It is characterized by profound congenital sensorineural hearing loss and a prolonged QT interval on electrocardiogram (ECG), which can lead to life-threatening arrhythmias. JLNS is considered a subtype of long QT syndrome (LQTS) and typically presents in early childhood. Without treatment, the condition carries a high risk of sudden cardiac death, but with early diagnosis and proper management, outcomes can improve significantly.

Causes

Jervell and Lange-Nielsen syndrome is caused by mutations in either the KCNQ1 or KCNE1 gene. These genes encode proteins involved in potassium ion transport in both the heart and the inner ear. Mutations disrupt the normal flow of potassium ions, leading to delayed repolarization of the heart (prolonged QT interval) and impaired hearing function. The condition is inherited in an autosomal recessive manner, meaning a child must inherit two copies of the mutated gene (one from each parent) to develop the syndrome.

Symptoms

JLNS presents with a distinct set of symptoms affecting both the heart and hearing. Common features include:

• Profound bilateral sensorineural hearing loss present at birth

• Prolonged QT interval on ECG, which can cause:

  • Fainting spells (syncope), especially during stress, exercise, or sudden noise

  • Seizure-like episodes due to cerebral hypoperfusion

  • Sudden cardiac arrest or sudden death, often during childhood

• No structural heart defects — the heart appears normal anatomically

• Normal intelligence and physical development apart from the cardiac and auditory manifestations

Diagnosis

Early diagnosis of JLNS is critical to prevent cardiac complications. Diagnostic steps include:

• Newborn hearing screening revealing bilateral sensorineural hearing loss

• ECG showing a markedly prolonged QT interval (typically >500 ms)

• Genetic testing confirming mutations in the KCNQ1 or KCNE1 gene

• Family history evaluation, though many parents are asymptomatic carriers

• Exercise or stress tests and Holter monitoring to assess cardiac risk

Treatment

JLNS requires lifelong management to reduce the risk of arrhythmias and sudden death. Treatment options include:

• Beta-blockers (e.g., propranolol or nadolol) to reduce the heart’s response to adrenaline and prevent arrhythmic events

• Implantable cardioverter-defibrillator (ICD) in high-risk individuals or those who have survived cardiac arrest

• Pacemaker implantation in selected cases with severe bradycardia or pauses

• Hearing aids or cochlear implants to manage hearing loss and support language development

• Strict avoidance of QT-prolonging medications and activities that may trigger arrhythmias

• Education and genetic counseling for the patient and family

Prognosis

The prognosis of Jervell and Lange-Nielsen syndrome depends heavily on early diagnosis and adherence to treatment. Without management, the risk of sudden death is high, particularly during childhood. With appropriate medical therapy and lifestyle adjustments, many individuals can live into adulthood with reduced arrhythmic events. However, the condition is lifelong and requires regular follow-up with cardiology and audiology specialists. Early intervention for hearing loss also plays a vital role in promoting speech and educational development.