Abstract: Provided are transgenic mice genetically engineered for a deficiency of the heart-skeletal muscle isoform of the adenine nucleotide translocator protein (Ant1). These mice exhibit histological, biochemical and physiological signs of deficiency in oxidative phosphorylation and energy generation, and these mice provide the first animal model for mitochondrial myopathy and hypertrophic cardiomyopathy. This animal model is used in methods for testing compounds for therapeutic value in treating failure to exchange ATP and ADP across the mitochondrial inner membrane, OXPHOS deficiency and in treating cardiac hypertrophy.