Abstracts

Rationale: Knowledge of mitochondria and the relationship of mitochondrial dysfunction to human diseases have evolved over the past century. The clinical manifestations of mitochondrial diseases are variable because mitochondria exist in multiple organs. Among them, central nervous system (CNS) is frequently affected because it needs more ATPs to carry out cellular work. Here we report the epileptic seizures in mitochondrial diseases in infants and children in Taiwan. Methods: From 1983 to 2007, we collected 59 cases, 35 male and 24 female, aged from 3 months to 18 years. The diagnosis of mitochondrial diseases was made by (1) electron microscopy of muscle biopsy showing abnormal mitochondrial configurations, and (2) positive mitochondrial genetic analysis, or (3) ragged-red fiber by histiochemistry stains of muscle biopsy. We retrospectively analyzed the epileptic seizures in patients with mitochondrial diseases.Results: 28 out of 59 cases (47.5%) were specific mitochondrial syndromes (SMS) and 31 cases (52.5%) belonged to non syndromic mitochondrial disease (NSMD). 21 cases (35.6%) had no seizures, 12 were SMS and 9 were NSMD. 16 out of 28 cases (57.1%) in the group of SMS had seizures: 7 generalized seizures in terms of myoclonic and generalized tonic and/or clonic seizures, 5 focal seizures, 2 unclassified seizures, and 2 mixed seizure types. 21 out of 31 cases (71.0%) in NSMD had seizures: 10 generalized seizures, 6 focal seizures, 2 unclassified seizures, and 4 mixed seizure types. 53 of 59 cases had done EEG., 7 normal EEG, 18 epileptiform discharges in terms of focal spikes, sharp waves or hypsarrhythmia, and 28 nonspecific findings, i.e. background slow or intermittent polymorphic slow waves. 32 out of 38 cases (84.2%) with seizures had developmental delay (DD) or psychomotor retardation (PMR).Conclusions: The epileptic seizures in mitochondrial diseases in infants and children were not uncommon (64.4%). Most of them were NSMD. All of them were refractory, most cases were associated with DD and PMR. Neurologists should be considered mitochondrial disorders in patients with refractory seizures and DD or PMR.