Late diagnosis of Jervell and Lange-Nielsen syndrome in two sisters with homozygous KCNQ1 mutation

Jervell and Lange-Nielsen syndrome is a rare inherited disorder characterised by sensorineural hearing loss and a prolonged corrected QT interval, predisposing to malignant arrhythmias. We describe two adult sisters diagnosed after recurrent syncope. Genetic testing confirmed a homozygous KCNQ1 mutation. Awareness of this condition, even in adulthood, is essential to ensure diagnosis, appropriate treatment, and prevention of sudden cardiac death.