184 Long QT syndrome -a case report

Abstract

<h3></h3> Timothy syndrome is a rare genetic disorder characterized by an abnormally prolonged cardiac ‘repolarization’ time (long QT interval). This predisposes individuals to arrhythmias, cardiac arrest and sudden death. Other features associated with this syndrome are dysmorphic facial features, webbing of fingers and/or toes (syndactyly); congenital heart defects, developmental delays and autism. We want to report a case of Timothy syndrome, incidentally detected post induction for orchidopexy <h3>Background</h3> TS is an extremely rare genetic disorder of the L-type cardiac channel Cav1.2 encoded by CACNA1C. The syndrome is characterized by multisystem abnormalities consisting of QT prolongation, congenital heart defects, syndactyly, facial dysmorphism, and neurological symptoms. <h3>Case Report</h3> 8yr old boy was admitted to hospital for elective left orchidopexy, during induction developed 2degree AV block with T Talternans, maintained reasonable cardiac output throughout, QTc 504 msec. Past medical history an episode of syncope needing hospitalization. Currently being evaluated for autism. Physical exam was normal. Holter, showed QTc prolongation with T alternans. Genetic testing showed he is positive gene mutation CACNA1C. Parents have been counselled for the need for implantable defibrillator. He has been given external automated defibrillator in the meantime. Currently on nadolol 40 mg OD, parents are awaiting gene testing. <h3>Discussion</h3> Classic timothy syndrome (TS) is a rare genetic disorder with dysfunction in multiple organ systems, clinically characterized by long QT syndrome and syndactyly. Timothy syndrome was first described in 1992. Classic TS is caused by a single missense mutation G406R of exon 8A of the Cav1.2 L-type calcium channel gene (CACNA1C) and is inherited in an autosomal dominant fashion, although it usually is the result of a de novo mutation. Patients with TS are prone to life threatening ventricular arrhythmias as a consequence of prolonged QT interval. Since the affected gene is widely expressed in multiple adult and foetal tissues including gastrointestinal system, brain, lungs, immune system and testis, extracardiac manifestations are common. The risk for life-threatening ventricular tachyarrhythmia is the limiting factor of TS. Since ventricular tachyarrhythmia is the leading cause of death in patients with TS, effective anti-arrhythmic medication and an implantable cardioverter defibrillator are the mainstay of therapy Conclusions Timothy syndrome is a rare congenital arrhythmia disorder with dysfunction in multiple organ systems. Patients are at high risk for sudden death due to life threatening ventricular tachyarrhythmia. Implantation of an ICD at a very young age may be the best means to prevent sudden death.