Because the condition does not become apparent until middle or late adult life, it is usually not possible to decide with any reliability whether offspring will eventually develop the condition. As with other muscle diseases, establishing the correct diagnosis relies heavily upon the experience of the doctor making the diagnosis. Not a great deal of research has yet been directed at this condition, in part because it is rare and also because it is relatively mild compared with other muscle disorders. Genetic samples from families all over the world will need to be pooled and studied to try and track down the genetic defect responsible for the condition. As the site of the gene is narrowed down, so pre-natal and carrier testing becomes more likely.
Mitochondria are very small structures that are present within every cell in the body.
They are vitally important for the chemical processes that generate the energy required to keep the cell alive and functioning normally. However, mitochondria are unique in that they also have a small amount of their own DNA which is responsible for producing some of the mitochondrial proteins. Another unique feature is that this mitochondrial DNA is always inherited from the mother, not the father. Ptosis is the first feature, followed by progressive limitation of the range of eye movements. Diplopia is uncommon.