SCN2A mutation in an infant presenting with migrating focal seizures and infantile spasm responsive to a ketogenic diet.

SCN2A mutations have been identified in various encephalopathy phenotypes, ranging from benign familial neonatal-infantile seizure (BFNIS) to more severe forms of epileptic encephalopathy such as Ohtahara syndrome or epilepsy of infancy with migrating focal seizure (EIMFS). Thus far, no particularly effective treatment is available for severe epileptic encephalopathy caused by SCN2A mutations in children. We present the case of a boy who developed seizures on the third day of life and received a diagnosis of EIMFS based on his clinical presentations and electroencephalography reports. Antiepileptic drugs, namely oxcarbazepine, phenytoin, valproate, levetiracetam, and clonazepam, as well as adrenocorticotropic hormone therapy failed to reduce the severity of the seizures. Seizure pattern changed to infantile spasm with extensor thrust since 5 months of age. A ketogenic diet consisting of a medium-chain triglyceride recipe was introduced at 8 months of age and the seizures were resolved in the following 10 months. A de novo mutation in SCN2A (c.573G > T; p.W191C) was proven through next-generation sequencing.