SCN1A and epilepsy of infancy with migrating focal seizures: EIMFS is a severe, drug-resistant, early-onset epilepsy encephalopathy in which variants in the KCNT1, SCN1A, SCN8A, SCN2A, PLCB1, KCNT1, SLC25A22, TBC1D24 and SLC12A5 genes as well as 16p11.2 duplication have been reported.