FHM3 is a rare subtype of familial hemiplegic migraine (FHM) caused by mutations in the neuronal sodium channel gene SCN1A (1). Only five FHM3 mutations have been described in a few families since the identification of SCN1A as the third FHM gene in 2005 (1–4). In the present issue of Cephalalgia, Weller et al. (5) report the identification of two novel SCN1A FHM3 mutations in two families with...

Genetic epilepsy with febrile seizures plus (GEFS(+)) is an inherited epilepsy that can result from mutations in at least four ion channel subunits. The majority of the known GEFS(+) mutations have been identified in SCN1A, the gene encoding Nav1.1 α-subunit. Protein kinases as critical modulators of sodium channels have been closely related to the genesis of epilepsy. However, little is known ...

PURPOSE To review our cohort of patients with Dravet syndrome and determine if patients with SCN1A mutations can also express mitochondrial disease due to electron transport chain dysfunction. METHODS A retrospective chart review was used to describe clinical manifestations and retrieve biochemical testing, neuroimaging, gene sequencing, and electroencephalographic results of patients express...

BACKGROUND Pertussis vaccination has been alleged to cause an encephalopathy that involves seizures and subsequent intellectual disability. In a previous retrospective study, 11 of 14 patients with so-called vaccine encephalopathy had Dravet syndrome that was associated with de-novo mutations of the sodium channel gene SCN1A. In this study, we aimed to establish whether the apparent association...

The majority of children with Dravet syndrome (DS) are caused by de novo SCN1A mutations. To investigate the origin of the mutations, we developed and applied a new method that combined deep amplicon resequencing with a Bayesian model to detect and quantify allelic fractions with improved sensitivity. Of 174 SCN1A mutations in DS probands which were considered "de novo" by Sanger sequencing, we...

Commentary Dravet syndrome is an infant-onset epileptic encephalopathy characterized by generalized clonic, tonic–clonic, or hemi-clonic seizures. Patients subsequently develop other types of seizures, including myoclonic, absence, or partial seizures. Seizures are often refractory to conventional antiepileptic drugs and lack ofadequate seizure control is correlated with poor outcomes. Developm...

Voltage-gated Na(+) channels are the workhorses of spike generation and propagation in excitable cells. Mutations in Na(+) channel genes have been identified in disorders causing episodic dysfunction of heart, skeletal muscle, and brain. Lossin and colleagues from Al George's lab report in this issue of Neuron that three missense mutations of SCN1A found in a dominant epilepsy syndrome disrupt ...

Mutations in the SCN1A gene have commonly been associated with a wide range of mild to severe epileptic syndromes. They generate a wide spectrum of phenotypes ranging from the relatively mild generalized epilepsy with febrile seizures plus (GEFS+) to other severe epileptic encephalopathies, including myoclonic epilepsy in infancy (SMEI), cryptogenic focal epilepsy (CFE), cryptogenic generalized...

Generalized epilepsy with febrile seizures plus (GEFS+) is an autosomal dominant familial syndrome with a complex seizure phenotype. It is caused by mutations in one of 3 voltage-gated sodium channel subunit genes (SCN1B, SCN1A, and SCN2A) and the GABA(A) receptor gamma2 subunit gene (GBRG2). The biophysical characterization of 3 mutations (T875M, W1204R, and R1648H) in SCN1A, the gene encoding...