Jervell

Jervell and Lange-Nielsen syndrome is a rare inherited condition characterized by severe disturbances in the heart's rhythm and hearing loss. This condition is one of many forms of long QT syndrome, which is a disorder that affects the heart's electrical activity. It is also included in a group of conditions known as congenital deafness with arrhythmia syndromes.

Signs and Symptoms

People with Jervell and Lange-Nielsen syndrome have a severe form of long QT syndrome. They experience repeated episodes of an irregular heartbeat (arrhythmia) which can lead to episodes of fainting (syncope), seizures, or sudden death. These episodes can be triggered by physical exertion or stress.

In addition to heart problems, individuals with Jervell and Lange-Nielsen syndrome are born with severe to profound sensorineural hearing loss. Sensorineural hearing loss is caused by abnormalities in the inner ear or the nerve pathways from the inner ear to the brain.

Causes

Jervell and Lange-Nielsen syndrome is caused by mutations in the KCNQ1 or KCNJ2 gene. These genes provide instructions for making proteins that form channels across cell membranes. These channels transport positively charged atoms (ions) in and out of cells. In the heart, these ion channels play critical roles in maintaining the heart's normal rhythm. Mutations in either the KCNQ1 or KCNJ2 gene alter the structure or function of these channels, disrupting the flow of ions and leading to the heart rhythm abnormalities seen in Jervell and Lange-Nielsen syndrome.

Diagnosis

The diagnosis of Jervell and Lange-Nielsen syndrome is based on clinical criteria including a personal or family history of long QT syndrome, congenital sensorineural deafness, and characteristic findings on an electrocardiogram (ECG). Genetic testing can confirm the diagnosis.

Treatment

Treatment of Jervell and Lange-Nielsen syndrome is focused on preventing sudden death due to irregular heart rhythms. Medications such as beta blockers, which slow the heart rate, can be used. In some cases, an implantable cardioverter-defibrillator (ICD) may be needed.

See also

• Long QT syndrome
• Congenital deafness
• Arrhythmia

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