Abstracts

Rationale: SCN1A gene mutations have been associated with multiple epilepsy syndromes, most frequently Severe Myoclonic Epilepsy of Infancy (SMEI) and Generalized Epilepsy with Febrile Seizures Plus (GEFS ), but other epilepsies have also been reported including Temporal Lobe Epilepsy (TLE). Although MRI findings have been evaluated in SMEI and familial cases of GEFS , MRI has not been previously evaluated in an unrelated cohort of children with SCN1A and epilepsy. We report an ongoing retrospective review of patients with SCN1A gene mutations and epilepsy with specific focus on MRI findings in childhood. Methods: Review of the clinical and MRI data of all patients with SCN1A gene abnormalities detected between 2005 and 2010 was conducted. All patients included had documented abnormalities in SCN1A gene sequencing analysis. Results: Thus far, 15 patients with SCN1A gene mutation have been identified including 11 males and 4 females, however, one patient did not have an MRI available for review. All but 2 patients had onset of epilepsy within the first year of life and age at most recent MRI ranged from 10 months to 14 years. Three patients (20%) had evidence of mesial temporal sclerosis (MTS) with one patient having asymmetric bilateral abnormalities. Other MRI findings included 4 normal (26.7%), 3 with non-specific signal abnormalities (20%), 2 with generalized atrophy (13.3%) and 2 with other unrelated abnormalities (Chiari I, possible hemispheric asymmetry). Of the 3 patients with MTS, all had earlier normal MRI s (20 to 43 months prior) and were between 3.5 years and 7 years of age when MTS was observed. Only one of these patients had classic SMEI with alternating prolonged hemiclonic febrile seizures and myoclonic seizures. The other 2 patients had no history of prolonged febrile seizures. One patient had a history of simple febrile seizure, and the other had seizure onset associated with administration of vaccinations however it was unclear whether they were febrile. Conclusions: Our study is the first to look at a group of children with SCN1A gene mutation and MRI findings regardless of clinical phenotype. The patient group revealed 20% had MTS and most of the patients did not have a history of prolonged febrile seizures. Our study indicates that testing for SCN1A gene mutation should be considered in young children with epilepsy and MTS; however, further prospective studies are needed to determine the relationship between MTS and SCN1A.