Dilated cardiomyopathy due to a novel combination of TTN and BAG3 genetic variants: from acute heart failure to subclinical phenotypes

Dilated cardiomyopathy (DCM) is defined as left ventricular enlargement accompanied by systolic dysfunction not explained by abnormal loading conditions or coronary heart disease. The DCM clinical spectrum is broad, ranging from subclinical to severe presentation with progression to end stage heart failure. To date, different genetic loci have been found to have moderate/definitive evidence for causality in DCM and pathogenic variants in the TTN gene represent the main genetic determinant. Here, we describe a family in which the co-occurrence of two genetic hits, one in the TTN and one in the BAG3 gene, was associated with heterogeneous clinical presentation ranging from subclinical phenotypes to acute cardiogenic shock mimicking fulminant myocarditis. We hypothesize that at least some specific BAG3 genotypes could be related to DCM presenting with acute heart failure and suggest that patients and relatives carrying BAG3 pathogenic variants should be addressed to a tertiary-level heart care center.