Referenced in: none

Automatically associated channels: Nav1.1 , Slo1

Title: Epilepsy-associated dysfunction in the voltage-gated neuronal sodium channel SCN1A.

Authors: Christoph Lossin, Thomas H Rhodes, Reshma R Desai, Carlos G Vanoye, Dao Wang, Sanda Carniciu, Orrin Devinsky, Alfred L George

Journal, date & volume: J. Neurosci., 2003 Dec 10 , 23, 11289-95

PubMed link: http://www.ncbi.nlm.nih.gov/pubmed/14672992

Abstract
Mutations in SCN1A, the gene encoding the brain voltage-gated sodium channel alpha1 subunit (NaV1.1), are associated with at least two forms of epilepsy, generalized epilepsy with febrile seizures plus (GEFS+) and severe myoclonic epilepsy of infancy (SMEI). We examined the functional properties of four GEFS+ alleles and one SMEI allele using whole-cell patch-clamp analysis of heterologously expressed recombinant human SCN1A. One previously reported GEFS+ mutation (I1656M) and an additional novel allele (R1657C), both affecting residues in a voltage-sensing S4 segment, exhibited a similar depolarizing shift in the voltage dependence of activation. Additionally, R1657C showed a 50% reduction in current density and accelerated recovery from slow inactivation. Unlike three other GEFS+ alleles that we recently characterized, neither R1657C nor I1656M gave rise to a persistent, noninactivating current. In contrast, two other GEFS+ mutations (A1685V and V1353L) and L986F, an SMEI-associated allele, exhibited complete loss of function. In conclusion, our data provide evidence for a wide spectrum of sodium channel dysfunction in familial epilepsy and demonstrate that both GEFS+ and SMEI can be associated with nonfunctional SCN1A alleles.