Non-juvenile familial form of malignant catecholaminergic polymorphic ventricular tachycardia caused by a novel ryanodine receptor type 2 R4608Q mutation

Abstract

Catecholaminergic Polymorphic Ventricular Tachycardia (CPVT) is a rare inherited channelopathy, responsible for potentially lethal malignant arrhythmic episodes. The index case was a 58-year-old woman who experienced aborted sudden cardiac arrest. The initial complete diagnostic work up (including norepinephrine challenge) was completely negative. She was implanted with an entirely subcutaneous defibrillator. During her follow-up, she received an appropriate electrical shock (ventricular fibrillation). Three sisters had sudden cardiac deaths (SCD) without etiology in the family history. There were no additional reports of pregnancy loss, neonatal death, seizures or SCD in family members. The genetic analysis revealed a Ryanodine Receptor type 2 R4608Q missense variant in this proband. Unfortunately, before the result of the proband's genetic analysis, her daughter experienced a SCD, whilst being implanted with an implantable loop recorder ( Fig. 1 ). A comprehensive genetic analysis was performed in the whole family using Next Generation Sequencing. All the carriers were treated with Nadolol 80 mg per day, and the follow-up was uneventful after six months. A novel Ryanodine Receptor type 2 R4608Q mutation is described in a non-juvenile familial form of CPVT.