Jervell and Lange-Nielsen syndrome (JLNS) is an autosomal recessive cardioauditory
ion channel disorder characterized by congenital bilateral sensorineural
deafness and long QT interval. JLNS is a ventricular repolarization abnormality and is caused by mutations in the KCNQ1 or KCNE1 gene. It has a high mortality rate in childhood due to
ventricular tachyarrhythmias, episodes of
torsade de pointes which may cause
syncope or
sudden cardiac death. Here, we present a 4.5-year-old female patient who had a history of
syncope and congenital sensorineural
deafness. She had a
cochlear implant operation at 15 months of age and received an
implantable cardioverter defibrillator (ICD) at 3 years of age because of recurrent
syncope attacks. Five months after
cochlear implant placement, she could say her first words and is now able to speak. With β-blocker
therapy and ICD, she has remained
syncope-free for a year. On the current admission, the family visited the genetics department to learn about the possibility of prenatal diagnosis of sensorineural
deafness, as the mother was 9 weeks pregnant. A diagnosis of JLNS was established for the first time, and a homozygous missense mutation in the KCNQ1 gene (c.128 G>A, p.R243H) was detected. Heterozygous mutations of KCNQ1 were identified in both parents, thereby allowing future prenatal diagnoses. The family obtained prenatal diagnosis for the current pregnancy, and fetal KCNQ1 analysis revealed the same homozygous mutation. The pregnancy was terminated at the 12th week of gestation. The case presented here is the third molecularly confirmed Turkish JLNS case; it emphasizes the importance of timely genetic diagnosis, which allows appropriate genetic counseling and prenatal diagnosis, as well as proper management of the condition.