UTRN and neuromuscular disease caused by qualitative or quantitative defects of dystrophin: Given the ability of utrophin to act as a surrogate to compensate for dystrophin deficiency at the sarcolemma and the contribution of aberrant mitochondrial function to the dystrophic pathology, the purpose of this study was to test whether utrophin over-expression or absence could influence mitochondrial pathology caused by dystrophin deficiency.