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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 GA, 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.

Distal 11q deletion, previously known as Jacobsen syndrome, is caused by segmental aneusomy for the distal end of the long arm of chromosome 11. Typical clinical features include facial dysmorphism, mild-to-moderate psychomotor retardation, trigonocephaly, cardiac defects, and thrombocytopenia. There is a significant variability in the range of clinical features. We report herein a five-year-old girl with severe ophthalmological findings, facial dysmorphism, and psychomotor retardation with normal platelet function, in whom a de novo 11q23 deletion was detected, suggesting that distal 11q monosomy should be kept in mind in patients presenting with dysmorphic facial features and psychomotor retardation even in the absence of hematological findings.