Dravet syndrome or genetic (generalized) epilepsy with febrile seizures plus?

Dravet syndrome and genetic epilepsy with febrile seizures plus (GEFS+) can both arise due 10 mutations of SCN1A. the gene encoding the alpha 1 pore-forming subunit of the sodium channel. GEFS+ refers to a familial epilepsy syndrome where at least two family members have phenotypes that fit within the GEFS+ spectrum. The GEFS+ spectrum comprises a range of mild to severe phenotypes varying from classical febrile seizures to Dravet syndrome. Dravet syndrome is a severe infantile onset epilepsy syndrome with multiple seizure types, developmental slowing and poor outcome. More than 70%,, of patients with Dravet syndrome have mutations of SCN1A these include both truncation and missense mutations. In contrast, only 10% of GEFS+ families have SCN1A mutations and these comprise missense mutations. GEFS+ has also been associated with mutations Of genes encoding the sodium channel beta I subunit. SCN1B. and the GABA(A) receptor gamma 2 subunit. GABRG2. The phenotypic heterogeneity that is characteristic of GEFS+ families is likely to be clue to modifier genes. Interpretation of the significance of a. SCN1A missense mutation requires a thorough understanding of the phenotypes in the GEFS+ spectrum whereas a de novo truncation mutation is likely to be associated with a severe phenotype. Early recognition of Dravet syndrome is important as aggressive control of seizures may improve developmental outcome. (C) 2009 Elsevier B.V. All rights reserved.