Six cases of epilepsy and ring chromosome 20 are reported and 20 additional cases in the literature are reviewed from the National Epilepsy Center, Shizuoka Higashi Hospital, Japan. Seizures consisted of a prolonged confusional state, and the ictal EEG showed bilateral high-voltage slow waves with occasional spikes. Neurological exam and MRI were usually normal. Mental retardation or bordeline IQ was present in 5 of 6 cases. Seizures were refractory to AEDs. 
COMMNENT. Chromosome analysis may be indicated in children with drug refractory epilepsy and learning disabilities, despite the absence of dysmorphic features. Ring chromosome 20 in a child with gelastic and partial complex seizures was included in a section on mental retardation syndromes in Progress in Pediatric Neurology III, 1997;p384.