Phenotype and progression among patients with dilated cardiomyopathy and RBM20 mutations

Background: Over 70 genes that encode different cell components have been involved in the aetiology of dilated cardiomyopathy. Genotype-phenotype interactions are an unsolved problem, and to a large extent the effects of mutations in the expression mechanisms involved in the disease remain unknown, although associations are increasingly being established which have clinical and prognostic implications.

Methods and results: The objective of our work was to describe our population that has cardiomyopathy associated with mutations in the gene RBM20, and study the genotype-phenotype relationship. We studied 8 cases undergoing follow-up at our Unit, and collected data for demographic, clinical and diagnostic testing variables. The mean age on diagnosis was 55 years [52-59], with a median follow-up of 31.5 months [26.0-67.3]. It is worth noting that 62.5% of the patients in our group had a history of cardiomyopathy in first degree relatives, and 37.5% of them had a family history of sudden death. One of the genetic variations of the sample was shared by three subjects who had no apparent family relationship with each other, and this variation had not been described in controls. It is also interesting that arrhythmic events were found in 37.5% of the sample, and 50% of patients had an indication for implantable cardiac defibrillator.

Conclusion: This is the first analysis of patients with RBM20 mutations conducted in our country, and it indicates a profile with prominent arrhythmogenesis, a high penetrance of familial cardiomyopathy, and sudden death.