Lethal ventricular arrhythmia accompanied with myopalladin truncation mutation: a case report.

Background: Myopalladin (MYPN) is a structural protein in the Z-disk that plays an important role in mechanotransduction and signalling to the nucleus. Although MYPN mutations have been reported in various cardiomyopathies, their association with arrhythmogenic phenotypes and malignant ventricular arrhythmias remains poorly characterized. Case summary: A 25-year-old man developed ventricular fibrillation (VF) while at a golf driving range. The patient had a family history of sudden death in a maternal uncle and grandfather. Examinations were performed to determine the cause of VF, such as acute coronary syndrome, vasospastic angina, or concealed long QT syndrome, but no obvious cause was found. However, mild, diffuse impairment of left ventricular (LV) wall motion without LV dilatation was observed on transthoracic echocardiography and magnetic resonance imaging. A subcutaneous implantable cardioverter defibrillator was implanted. Whole-exome linkage analysis revealed an MYPN R763X truncating mutation in both the patient and his mother. The patient was diagnosed with arrhythmogenic left ventricular cardiomyopathy (ALVC) in the presence of a maternally inherited MYPN truncating mutation. No significant abnormalities were apparent in other genes associated with VF or cardiomyopathies. Discussion: This case suggests a possible involvement of MYPN truncating mutations in ALVC.