Biophysical characterization of a new SCN5A mutation S1333Y in a SIDS infant linked to long QT syndrome

FEBS Lett. 2009 Mar 4;583(5):890-6. doi: 10.1016/j.febslet.2009.02.007. Epub 2009 Feb 10.


Various entities and genetic etiologies, including inherited long QT syndrome type 3 (LQT3), contribute to sudden infant death syndrome (SIDS). The goal of our research was to biophysically characterize a new SCN5A mutation (S1333Y) in a SIDS infant. S1333Y channels showed the gain of Na(+) channel function characteristic of LQT3, including a persistent inward Na(+) current and an enhanced window current that was generated by a -8 mV shift in activation and a +7 mV shift in inactivation. The correlation between the biophysical data and arrhythmia susceptibility suggested that the SIDS was secondary to the LQT3-associated S1333Y mutation.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Base Sequence
  • Cell Line
  • Electrophysiology
  • Humans
  • Infant
  • Ion Channel Gating
  • Long QT Syndrome / complications*
  • Long QT Syndrome / genetics*
  • Long QT Syndrome / metabolism
  • Muscle Proteins / genetics*
  • Muscle Proteins / metabolism*
  • Mutation / genetics*
  • NAV1.5 Voltage-Gated Sodium Channel
  • Patch-Clamp Techniques
  • Serine / genetics
  • Serine / metabolism
  • Sodium Channels / genetics*
  • Sodium Channels / metabolism*
  • Sudden Infant Death / genetics*


  • Muscle Proteins
  • NAV1.5 Voltage-Gated Sodium Channel
  • SCN5A protein, human
  • Sodium Channels
  • Serine