Age and cause of death in mitochondrial diseases

We report on the age and the causes of death in 16 patients with mitochondr ial diseases. Nine patients with mitochondrial encephalomyopathy, lactic ac idosis, and stroke-like episodes (MELAS) died at a mean age of 34 years and three patients with chronic progressive external ophthalmoplegia at a mean age of 56 years. The causes of death were cardiopulmonary failure (n = 5), status epilepticus (n = 4), aspiration pneumonia (n = 2), pulmonary emboli sm (n = 2), renal failure (n = 1), metabolic disturbance (n = 1), and unkno wn causes (n = 1). Thus, many patients in this series died of medical compl ications, some of which may be prevented.