Clinical Insights in RNA-Binding Protein Motif 20 Cardiomyopathy: A Systematic Review.

Dilated cardiomyopathy (DCM) is a common cause of heart failure (HF) and heart transplantation (HTx), with genetic factors playing a significant role. In recent years, the RNA-binding protein motif 20 (RBM20), which affects the gene splicing of various proteins with different cellular functions, was identified as the first DCM gene with regulatory properties. Variants of RBM20 have been associated with severe forms of DCM. The aim of this critical systematic review was to analyse RBM20 cardiomyopathy clinical features and outcomes. According to PRISMA guidelines, a search was run in the PubMed, Scopus and Web of Science electronic databases using the following keywords: "RBM20"; "cardiomyopathy"; "arrhythmias"; "heart failure". A total of 181 records were screened, of which 27 studies were potentially relevant to the topic. Through the application of inclusion and exclusion criteria, eight papers reporting 398 patients with RBM20 pathogenic variants were analysed. The mean age at presentation was 41 years. Familiarity with cardiomyopathy was available in 59% of cases, with 55% of probands reporting a positive family history. Imaging data indicated a mild reduction of left ventricular ejection fraction (mean LVEF 40%), while tissue characterization was reported in 24.3% of cases, showing late gadolinium enhancement in 33% of patients. Composite outcomes of sustained monomorphic ventricular tachycardia or ventricular fibrillation occurred in 19.4% of patients, with 12% undergoing HTx. There were no gender differences in arrhythmic outcomes, while 96.4% of patients who underwent HTx were male. In conclusion, RBM20 cardiomyopathy exhibits a severe phenotypic expression, both in terms of arrhythmic burden and HF progression.