Spectrum of desmosomal gene variations in patients with arrhythmogenic right ventricular cardiomyopathy

Arrhythmogenic right ventricular cardiomyopathy (ARVC) is a hereditary myocardial disease with a high risk of sudden cardiac death. The most common genetic forms of the disease are associated with desmosomal gene mutations. Aim. To study the prevalence of desmosomal forms of ARVC and to analyze variations in the PKP2, DSG2, DSP, DSC2 and JUP genes in a sample of Russian patients with ARVC. Material and methods. Included patients with ARVC underwent resting electrocardiography (ECG), 24-hour Holter ECG monitoring, echocardiography, chest x-ray, myocardial biopsy (if indicated), contrast-enhanced cardiac magnetic resonance imaging. All patients underwent medical genetic counseling. Mutations in the PKP2, DSG2, DSP, DSC2, and JUP genes was detected using highthroughput sequencing on the IonTorrent platform, followed by Sanger sequencing of uncovered gene regions. The pathogenicity of identified genetic variations was assessed according to modern guidelines. Results. ARVC was established in 80 Russian unrelated patients. More than half of the probands (57%) in the study sample had definite diagnosis of ARVC, while 30% and 13% — borderline and possible ARVC, respectively. A positive family history of heart disease and/or SCD was noted in 30%. Genetic variants of pathogenicity class IV-V were detected in 15 (18,75%) probands in the PKP2, DSG2, DSP genes. The detection of genetic variants of pathogenicity class IV-V was different in the subgroups of patients with varying degrees of diagnosis reliability: 13 probands (28,3%) in the subgroup with definite ARVC and 2 probands (8,3%) in the subgroup with borderline ARVC. No genotype-positive probands were found in the subgroup with possible ARVC. Variations of unknown clinical significance were found in 13 (16,25%) probands. Conclusion. The diagnostic yield of the desmosomal genes PKP2, DSG2, DSP, DSC2, and JUP was 19% with initial diagnosis of ARVC. The detection of mutations was significantly higher in patients with definite ARVC and severe disease manifestations.