When circadian clock genes are mutated or disrupted, mitochondrial dynamics may lose circadian rhythm and become disordered, resulting in insulin resistance, cardiac lipotoxicity, excessive production of mitochondrial reactive oxidative species (ROS), mitochondrial Ca2+ mishandling, decreased mitochondrial membrane potential (MMP), impaired mitophagy, and endoplasmic reticulum (ER) stress, which are associated with the pathophysiology of DCM (9–11). The gene discussed is CLOCK; the disease is familial dilated cardiomyopathy.