Oculo cranio-somatic syndrome: mitochondrial alterations and lactic acidemia

We studied three patients whose main symptoms were ptosis, external ophthalmoplegia and variable weakness of various facial and somatic muscles. In two of the patients we found lactic acidosis at rest, and an excessive production of lactic acid after 15 minutes of exercise. Ischemic exercise resulted in sustained blood lactate elevation in one of the patients while lactate returned to normal in the others. The pathogenesis of this lactic acidosis is examined on the basis of ultrastructural alterations and by comparison with recent experiments. We concluded that the morphological and biochemical changes found in our patients are due to a condition of relative ischemia in the muscles.