Compound Heterozygous Triadin Mutation Causing Cardiac Arrest in Two Siblings

We present the case of two siblings who both presented with an out-of-hospital cardiac arrest at 2 years of age. Both siblings underwent internal cardiac defibrillator implantation and both had recurrent episodes of ventricular fibrillation (VF). A compound heterozygous mutation in the triadin gene was discovered; one of these mutations has been described previously in the homozygous state, and the other one is unreported. The combination of these mutations has resulted in a particularly arrhythmogenic phenotype, with cardiac arrest occurring at a very young age and recurrent episodes of VF despite β-blockade. Flecainide seems to have been very effective in preventing clinical arrhythmias for this particular mutation.