Jervell and Lange-Nielsen syndrome

Jervell and Lange-Nielsen syndrome, abbreviated JLNS, is a rare form of long QT syndrome that occurs together with severe hearing loss in both ears of the sensorineural type. People with the syndrome are at risk of abnormal heart rhythms called arrhythmias, which can lead to fainting, seizures or sudden death, because the heart muscle takes longer than usual to recharge between beats. The cause is genetic variants in genes that make ion channels carrying potassium out of cells. The condition is usually diagnosed with an electrocardiogram, and genetic testing can also confirm it. Management includes lifestyle measures, beta blockers and, in some cases, implantation of a defibrillator. It was first described by Anton Jervell and Fred Lange-Nielsen in 1957.