Epilepsy as manifestation of mitochondrial encephalopathy: Three clinical cases

We describe three patients in which epilepsy was the first important symptom of mitochondrial encephalomyopathy. In Case 1 (MERRF) myoclonus was associated with muscle weakness and ataxia. In case 2 and 3 (MELAS) focal seizures proceded impairment of intellectual function and stroke like episodes. Elevated lactic acidemia at rest and ragged red fibers at muscle biopsy were present in all patients. In case 2 and 3 biochemical studies on muscle omogenate were carried on and revealed defects in the mitochondrial respiratory chain which were located at cit. C oxidose in case 2 and NADH cit. C reductase in case 3. Clinical, electroencephalographic and cerebral CT scan data of our patients indicated that MERRF and MELAS syndromes could be considered two different clinical entities even if the pathogenesis is always a mitochondrial alteration. Furthermore, we found out some clinical disorders in patients relatives. We, therefore, confirm the hereditariety of this encehalopathy and our data do not exclude a non mendelian type of transmission.