A new Nav1.7 mutation in an erythromelalgia patient

Biochem Biophys Res Commun. 2013 Mar 1;432(1):99-104. doi: 10.1016/j.bbrc.2013.01.079. Epub 2013 Jan 30.


Gain-of-function missense mutations of SCN9A gene, which encodes voltage-gated sodium channel Nav1.7, alter channel's biophysical properties causing painful disorders which are refractory to pharmacotherapy in the vast majority of patients. Here we report a novel SCN9A mutation (ca.T3947C) in exon 20 in a 9 year old patient, not present in 200 ethnically-matched control alleles; the mutation substitutes the invariant valine 1316 residue within DIII/S5 by alanine (V1316A). Voltage-clamp studies show that Nav1.7 V1316A mutation hyperpolarizes activation (-9 mV), and enhances response to ramp stimuli (3-fold), changes that are predicted to cause hyperexcitability of DRG neurons. V1316A also hyperpolarizes steady-state slow-inactivation (-9.9 mV), which is predicted to attenuate the effect of this mutation on DRG neuron firing. These changes are consistent with previously characterized Erytheromelalgia associated mutations of Nav1.7.

Publication types

  • Case Reports

MeSH terms

  • Alanine / genetics
  • Amino Acid Sequence
  • Child
  • Erythromelalgia / genetics*
  • Erythromelalgia / physiopathology
  • Exons / genetics
  • Female
  • Ganglia, Spinal / physiology
  • HEK293 Cells
  • Humans
  • Molecular Sequence Data
  • Mutation, Missense
  • NAV1.7 Voltage-Gated Sodium Channel / genetics*
  • NAV1.7 Voltage-Gated Sodium Channel / metabolism
  • Valine / genetics


  • NAV1.7 Voltage-Gated Sodium Channel
  • SCN9A protein, human
  • Valine
  • Alanine