Jervell and Lange-Nielsen syndrome: A case report of a variant in the KCNQ1 gene in a Jordanian child

Jervell and Lange-Nielsen syndrome (JLNS) is a rare autosomal recessive disorder characterized by congenital bilateral sensorineural hearing loss and prolonged QTc interval, which predisposes patients to life-threatening arrhythmias. A 5-year-old girl presented with congenital hearing loss, recurrent syncopal episodes, and severe iron deficiency anemia. Electrocardiogram showed a prolonged QTc interval of 530 ms, and genetic testing identified a homozygous nonsense variant in the KCNQ1 gene (c.1480G>T; p.Glu494Ter). The patient was started on beta-blockers and high-dose iron therapy, which led to a reduction in syncopal episodes and improvement in hematological parameters. She was referred to an electrophysiology center for consideration of an Implantable cardioverter defibrillator (ICD) or possible left cardiac sympathetic denervation. This is the first documented case of JLNS with a KCNQ1 variant reported in Jordan, emphasizing the critical role of genetic testing in diagnosis and management.