JERVELL AND LANGE-NIELSEN SYNDROME

PREVALENCE IN DEAF CHILDREN AND ITS SIGNIFICANCE IN RELATION TO COUSIN MARRIAGES

Abstract

Objective: This study was carried out to find out the prevalence of Jervell and Lange Nielsen Syndrome (JLNS) in deaf school children for impaired hearing and to correlate this with consanguineous marriages. Setup: Schools for deaf and dumb children and Sheikh Zayed Medical College, Rahim Yar Khan. Design: Cross sectional, case control study. Period: 2006 - 2007. Methods: Electrocardiographs (ECG’s) of 114 congenitally deaf school children (ages 4-20 years) and also of 23 healthy children with normal hearing function of same age group were recorded. The corrected QT (QTc) interval of all 137 ECGs was evaluated by Bazett’s formula. Mean QTc of healthy children was taken as reference of normal QTc interval. The deaf children with normal QTc were labeled as control group. Patients with long QTc were further evaluated for JLNS by applying Schwartz’s criteria. We also calculated the relationship of the positive cases to consanguineous marriages. Results: We found that 28 deaf children out of 114 cases had QTc intervals longer than 0.44 seconds. This interval was significantly longer [P=0.008] than the QT interval in control group. As per Schwartz’s criteria, 15 out of 28 LQTs cases scored high points (3.5 to 5.5). The presence of consanguineous marriage was 100% in first pedigree of these 28 children. Conclusions: JLNS (an alarming arrhythmic disease associated with congenital deafness) is significantly present (24.6%) in Rahim Yar Khan’s deaf school children. The presence of cousin marriage was 100% in first pedigree of these children.