Generalized epilepsy with febrile seizures plus (GEFS+) is a rare autosomal dominant, familial condition with incomplete penetrance and variable expressivity. It includes a spectrum from commonly mild (such as febrile seizure alone) to rarely severe (including medically treatable generalized epilepsy, intractable generalized epilepsy, or in some cases Dravet syndrome) epilepsy. Individuals with GEFS+ often have febrile seizures (or FS+) in early childhood, followed by occasional tonic, clonic, myoclonic, or absence seizures that respond to medication and remit by late childhood or early adolescence. Intermediate phenotypes with myoclonic, absence, or focal epilepsy are also included. More than 95% of individuals with GEFS+ have a parent with the same SCN1A pathogenic variant (Gennaro et al, 2003); however, the risk of developing seizures is less than 100% because of reduced penetrance, estimated to be 70% for the GEFS+ phenotype (Bonanniet al, 2004). In summary, SCN1A is definitively associated with Generalized Epilepsy with Febrile Seizures Plus. This has been repeatedly demonstrated in both the research and clinical diagnostic settings, and has been upheld over time.
The GenCC data are available free of restriction under a CC0 1.0 Universal (CC0 1.0) Public Domain Dedication. The GenCC requests that you give attribution to GenCC and the contributing sources whenever possible and appropriate. The accepted Flagship manuscript is now available from Genetics in Medicine (https://www.gimjournal.org/article/S1098-3600(22)00746-8/fulltext).
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