Febrile seizures (FS) characterize the majority of childhood seizures, it is well recognized highly inheritance in family of children with FS. Several genetic loci related to FS had been defined imply the genetic heterogeneity of FS. Nevertheless, molecular genetic approaches toward understanding FS related epilepsies have been explored this decade; especially sodium channel mutation 1α (SCN1A). Among them, generalized epilepsy with FS plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI) are highlighted. This review demonstrates recent development from clinics to genetics of FS and the update of genetics in FS associated epilepsy in SCN1A mutation and related epileptic syndromes.