What are symptoms of mitochondrial myopathy?

Many symptoms: The mm are a group of disorders due to dysfunction of the mitochondria, which are the energy producing parts of the cell. Nerve and muscle cells need a great deal of energy and so are most affected. Symptoms depend on which enzymes / proteins are dysfunctional, but muscle, brain, heart and eye function can be affected. See: http://www.Ninds.Nih.Gov/disorders/mitochondrial_myopathy for more info.