Single-cell RNA-seq of the heart from patients with heart failure revealed that activation of DNA damage response and TGF-β signaling and downregulation of genes related to mitochondrial metabolism are hallmarks of cardiomyocytes of patients with DCM (31, 32) and that dopamine receptor D1 (DRD1) positive cardiomyocytes are characteristic for DCM patients with fatal ventricular arrhythmias (33). The gene discussed is DRD1; the disease is heart failure.