Abstract 11990: LMNA Cardiomyopathy Mimicking Arrhythmogenic Right Ventricular Cardiomyopathy

Abstract

Background and Objectives: Arrhythmogenic right ventricular cardiomyopathy (ARVC) is an inherited disease characterized by RV dilatation and ventricular arrhythmias. Desmosomal gene mutations are the major cause of ARVC. LMNA mutations have been known to lead dilated cardiomyopathy, other systemic diseases, and more recently, ARVC. In this study, we performed extensive genetic screening for LMNA in ARVC patients and assessed the clinical characteristics of patients with LMNA mutations. Methods: Study cohort consisted of 57 ARVC probands (definite; 45). Coding exons of LMNA, 4 desmosomal protein genes (PKP2, DSP, DSG2, DSC), and also 3 long QT syndrome related genes (KCNQ1, KCNH2, SCN5A) were amplified and sequenced by using illumina next generation sequencer. Clinical characteristics of LMNA mutation carriers and those of desmosomal mutation carriers were compared by using student t test. Results: Among 57 clinically-diagnosed ARVC probands, we identified desmosomal mutations in 32 probands (56.1%) and two LMNA mutations in two probands. The first LMNA mutation, p.M1K was detected in 62-year-old male, and the second one, p.W514X was in 70-year-old male. Both patients showed RV dilatation, non-sustained ventricular tachycardia, and complete atrioventricular block. His younger brother also died from ARVC. The proband’s daughter and son, who are currently in their 30s, have the same M1K mutation, however, have not had any signs of ARVC yet. In the family member with W514X mutant, the proband’s father suddenly died in his 40s and 45-year-old daughter who had the same W514X mutation, showed RV dilatation and brady-AF. In probands with LMNA mutations compared to those with desmosomal mutations, the age of onset was significantly older (38.6±18.1 vs 60.0±2.8), and their heart rate was significantly slower (61.1±12.5 vs 47±1.4). Both probands with LMNA mutations underwent pacemaker therapy, which is rare in patients with desmosomal mutations (2/2 vs 1/32 ). In family members with LMNA mutations, none of mutation carriers had showed ARVC until their 50s. Conclusion: Our patients with LMNA mutations developed ARVC with bradyarrhythmia after age of 50. Genetic screening for LMNA gene is important for ARVC, especially in cases with bradycardia.