SCN5A and familial dilated cardiomyopathy: Since TTN is the most common disease gene associated with DCM (accounting for up to 25% of cases), and the proband’s phenotype is consistent with TTNtv-linked DCM (LVRR) rather than SCN5A-linked DCM (no severe conduction defects or left or right bundle branch block), the TTNtv c.6790+3A>G variant is likely the pathogenic variant in this case.