Prevalence of Jervell-Lange Nielsen syndrome in children with congenital bilateral sensorineural hearing loss

Objective: Long QT syndrome (LQTS) is an inherited car-diac ion channel disorder (channelopathy) that is character-ized by prolonged QT intervals on the electrocardiography (ECG) and possess the risk of sudden cardiac death (SCD). Jervell-Lange Nielsen syndrome (JLNS) is a specific sub-type of LQTS that is accompanied by congenital sensori-neural hearing loss, inherited autosomal recessively, and higher risk of SCD. In this study, we aimed to investigate JLNS prevalence in deaf children attending special schools for hearing loss, located in our province. Methods: An ECG screening program was conducted in 6 special schools for children with hearing loss in istanbul and a total of 440 students between 6 and 18 years old were included. Corrected QT interval (QTc) was calculated using the Bazett formula. Notably, 51 students, detected with any abnormal finding on ECG, were invited to our center for a comprehensive examination. Results: A total of 8 patients were found with a prolonged QT interval. JLNS was diagnosed in 4 (0.9%) patients. In addition, 2 students had already been diagnosed with JLNS at another center earlier. The other 2 students, being sib-lings, were newly diagnosed with JLNS; and appropriate treatment was initiated. Genetic testing revealed a patho-logical homozygous mutation in KCNQ1 gene. The younger sibling (Case 1), who possessed a QTc of greater than 500 ms and a history of syncope, which was very suspicious for SCD, was implanted an implantable cardioverter-defibrilla-tor. Propranolol treatment was initiated for both siblings. Conclusion: JLNS should be carefully considered and screened, especially in patients with a history of congenital deafness.