Could you explain what is mitochondrial myopathy?

Disease where: The mitochondria in muscles are not functioning properly and cause muscle weakness or atrophy of the muscle. The mitochondria is the "powerhouse" of the cell. When they do not function correctly, the cells loose power and either are not efficient or cause cell death. Theres many different causes of this type of myopathy. See http://mda.Org/disease/mitochondrial-myopathies hope that helps!