TPM1 and familial dilated cardiomyopathy: Three isogenic iPSC cell lines were used to study the impact of TPM1 HCM/DCM mutations on cardiomyocyte function: WT, WT with a CRISPR/Cas9–induced homozygous TPM1E62Q/E62Q mutation (HCM-causing), and WT with a CRISPR/Cas9–induced homozygous TPM1E54K/E54K mutation (DCM-causing).