(Myers, et. al. 2017). GEFS+ (Generalized Epilepsy with Febrile Seizures Plus) is somewhere near the middle of the spectrum of SCN1A-related disorders that places migraines or simple febrile seizures at the mild end and Dravet syndrome at the severe end. It has traditionally been thought of as a familial epilepsy syndrome because the mutations found in patients with GEFS+ are often inherited, while the mutations found in Dravet syndrome are usually de novo (meaning new to the child, or not inherited from either parent). This article describes seven patients with de novo SCN1A mutations who have GEFS+ but not Dravet syndrome, suggesting that GEFS+ is not always a familial epilepsy syndrome. Early development was normal in all seven cases, but learning difficulties and/or language impairment was found later in some of the patients.

Myers KA, Burgess R, Afawi Z, Damiano JA, Berkovic SF, Hildebrand MS, Scheffer IE. De novo SCN1A pathogenic variants in the GEFS+ spectrum: Not always a familial syndrome. Epilepsia. 2017 Jan 13. doi: 10.1111/epi.13649. [Epub ahead of print] PubMed PMID: 28084635. https://www.ncbi.nlm.nih.gov/pubmed?cmd=historysearch&querykey=4