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Article
Epilepsy-Associated Dysfunction in the Voltage-Gated Neuronal Sodium Channel SCN1A
J. Neurosci. (2003)
  • Christoph Lossin
  • T. H. Rhodes, Vanderbilt University
  • R. Desai, Vanderbilt University
  • C. Vanoye, Vanderbilt University
  • S. Caniciu, New York University
  • O. Devinsky, New York University
  • A. L. George, Vanderbilt University
Abstract
Mutations in SCN1A, the gene encoding the brain voltage-gated sodium channel 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.
Keywords
  • epilepsy,
  • sodium channel,
  • GEFS+,
  • SMEI,
  • SCN1A,
  • electrophysiology
Publication Date
December 10, 2003
Citation Information
Christoph Lossin, T. H. Rhodes, R. Desai, C. Vanoye, et al.. "Epilepsy-Associated Dysfunction in the Voltage-Gated Neuronal Sodium Channel SCN1A" J. Neurosci. Vol. 23 Iss. 36 (2003)
Available at: http://works.bepress.com/christoph_lossin/1/