As mutations in NKX2-535, 36, 37 and TBX538, 39, 40 are found in patients with conduction defects, a recent study has identified two novel IRX3 mutations, R421P and P485T, in idiopathic VF patients without other genetic defects in well-known arrhythmogenic genes15. This evidence concerns the gene IRX3 and ventricular fibrillation.