Epilepsy in inherited metabolic disorders: a pediatric series

AIM: Our study aims at further defining the characteristics of epilepsy in Inherited Metabolic Disorders (IMDs). METHODS: We reviewed the medical records of 345 patients with IMDs followed at the Metabolic Diseases Unit of our Department of Pediatrics and found the presence of an epileptic syndrome in 45 cases. An overview is given based on various criteria such as pathogenetic background, seizure type, age of onset, EEG, neuroimaging data, treatability. Seizure types were: focal (24 patients), generalized (13 patients), febrile (3 patients), and hypoglycemic (8 patients with glycogenoses). Some patients presented with more than one type of seizures. Age of onset was mainly during the first year of life (N.=19), between 2 and 6 years in 13 patients, and after the 6th year in 9 patients. RESULTS: Available EEGs showed either focal (N.=21) or generalized epileptiform abnormalities (N.=11); multifocal paroxysms were evident in 3 patients while the remaining 3 patients had normal findings. Available neuroimages (CT/MRI) showed either normal findings (N.=6) or white matter abnormalities (N.=6), cerebral and/or cerebellar cortical atrophy (N.=11), hydrocephalus (N.=1), corpus callosum hypoplasia (N.=2), pontocerebellar hypoplasia (N.=1), gliosis in trigone area (N.=4). Most patients showed a favorable response to antiepileptic treatment (AEDs) with either complete control or reduced seizure frequency. CONCLUSION: IMDs are a relatively rare cause of epilepsy in children but their diagnosis is very important with respect to treatment, prognosis and genetic counselling.