These findings indicate that cardiac-specific ablation of NDUFAB1 leads to dilated cardiomyopathy accompanied by cardiomyocyte hypertrophy, interstitial fibrosis, and systolic and diastolic dysfunction, eventually resulting in heart failure and sudden death, revealing an essential role of NDUFAB1 in cardiac function. The gene discussed is NDUFAB1; the disease is dilated cardiomyopathy.