Generalized epilepsy with febrile seizures plus
![Figure 1. Schematic structure of SCN1B with GEFS+ type 1 mutations shown in red. The single red spot is the C121W mutant at the disulfide bond (black) and the stretch of red the I70_E74del mutation.](/Images/godic/202501/15/Sodium_channel_beta_GEFS_plus0927.png")
Generalized epilepsy with febrile seizures plus (GEFS+) is a syndromic autosomal dominant disorder where afflicted individuals can exhibit numerous epilepsy phenotypes. GEFS+ can persist beyond early childhood (i.e., 6 years of age). GEFS+ is also now believed to encompass three other epilepsy disorders: severe myoclonic epilepsy of infancy (SMEI), which is also known as Dravet's syndrome, borderline SMEI (SMEB), and intractable epilepsy of childhood (IEC). There are at least six types of GEFS+, delineated by their causative gene. Known causative genes are the sodium channel α subunit genes SCN1A, an associated β subunit SCN1B, and a GABAA receptor γ subunit gene, GABRG2 and there is another gene related with calcium channel the PCDH19 which is also known as Epilepsy Female with Mental Retardation. Penetrance for this disorder is estimated at approximately 60%.