Over the past several years, genetic testing has emerged as an essential tool in the etiological study of dilated cardiomyopathy (DCM). Being able to pinpoint the etiology of DCM may lead to a specific individualized treatment, besides the prognostic and family implications, if a genetic cause is identified. Discovery of new genes, alongside improvements in genetic sequencing, implies a higher benefit than previously reported.

Determining and quantifying the current yield of genetic studies in an international cohort of patients with DCM.

Observational study of retrospective cohorts in two university hospitals (France and Spain). All genetic panels indicated in the study of DCM, carried out between December 2018 and December 2020, have been reviewed. Both centers have used the next-generation sequencing technique, involving panels of 80 and 83 genes, depending on the availability in each center. The encountered variants were classified by each center as: benign, of uncertain significance or disease-causing (DCV).

79 patients have undergone genetic testing. Mean age was of 52 years, with 29% of females. One quarter of the patients had family history of DCM. A cardiac magnetic resonance imaging (CMRI) was performed in 72%. In 54% of the cases (n=43), a mutation was found, giving rise to 64 variants, of which 51% were described as DCV (n=33, 42% of the total cohort–Figure 1). More than half (54%) of the DCV concerned genes encoding the titin, myosin binding protein C, and filamin C. We identified a DCV in 8/14 (57%) of patients with family history of DCM and in 15/18 (83%) of patients with late gadolinium enhancement in the CMRI.

Our results reflect the current practice of genetic testing, suggesting a higher yield (42%) compared with what is described in literature.