RBM20 and familial dilated cardiomyopathy: To determine whether DCM-associated mutations in the human D2 sequence element promote RBM20 relocalization, the R641Q (20), T653I (40), and P661R (ClinVar accession: VCV000965264.3) mutations were engineered into human RBM20, and the mutant constructs were expressed in H9c2 cells.