Pattern of childhood epilepsies with neuronal migrational disorders in Oman

Neuronal migrational disorders form a significant cause of psychomotor delay and intractable epilepsy in children. Pediatric neurology services are available at Sultan Qaboos University Hospital, Muscat, Oman, which is a tertiary care hospital for the whole country. The children undergoing evaluation for developmental delay and epilepsy formed the subjects of the study. Data were analyzed from children found to have neuronal migrational disorders on imaging (computed tomography [CT] or magnetic resonance imaging [MRI]). There were 40 cases of neuronal migrational disorders. Corpus callosum agenesis and lissencephaly or pachygyria formed the major group. There were 22 cases of corpus callosum agenesis, 12 of lissencephaly or pachygyria, 2 of schizencephaly, and 1 each of polymicrogyria, holoprosencephaly, hydranecephaly, and hemimegalencephaly. Nineteen of these 40 (47.5%) cases of neuronal migrational disorders had epilepsy. The break-down was 8 of 22 cases of corpus callosum agenesis (36%), 7 of 12 (58.3%) cases of lissencephaly or pachygyria, and 1 each of polymicrogyria, hydranencephaly, and hemimegalencephaly. The family history of developmental delay, similar to the index case, was present in two children with lissencephaly. However, the brain imaging did not reveal the abnormality. The types of seizures were infantile spasms in five, tonic-clonic in nine, myoclonic in two, partial in one, and mixed in five. Nineteen of 40 cases of neuronal migrational disorders had epilepsy. Only 2 of 19 (10.5%) with epilepsy had good seizure control. This raises the possibility of more and more surgical intervention in the management of such cases. Neuronal migrational disorders are related to exogenous and genetic factors from the 6th to 26th weeks of gestation. Molecular and genetic research is defining the mechanism of these disorders. This could help in early diagnosis, prevention, and eventual gene therapy in such conditions.