Migrating focal seizures of infancy associated with pathogenic variants in PACS2

Epilepsy of infancy with migrating focal seizures (EIMFS) is a genetically heterogeneous disorder presenting with early infantile epileptic encephalopathy. Here we report a PACS2 pathogenic variant typically associated with a developmental and epileptic encephalopathy in an infant presenting with clinical and electrographic findings suggestive of EIMFS who, however, responded well to low dose Carbamazepine and achieved normal developmental milestones. This case highlights an unexpected phenotypic presentation of a recurrent PACS2 variant and suggests an effective therapeutic approach to this clinical presentation.