Novel mutations in the KCND3-encoded Kv4.3 K+ channel associated with autopsy-negative sudden unexplained death

Hum Mutat. 2012 Jun;33(6):989-97. doi: 10.1002/humu.22058. Epub 2012 Mar 27.


Heritable arrhythmia syndromes, including Brugada syndrome (BrS) and idiopathic ventricular fibrillation (IVF), may serve as the pathogenic basis for autopsy-negative sudden unexplained death (SUD) and sudden infant death syndrome (SIDS). Emerging evidence has linked perturbations in the transient outward current (I(to) ) conducted by the KCND3-encoded Kv4.3 pore-forming α-subunit to BrS or IVF. However, the contribution of KCND3 mutations to autopsy-negative SUD/SIDS is unknown. To investigate the potential association between KCND3 and SUD/SIDS, mutational analysis of KCND3 was conducted in 123 SUDS and 292 SIDS victims using polymerase chain reaction, denaturing high-performance liquid chromatography, and direct sequencing. Overall, one SIDS case (<1.0%) and two SUDS cases (1.6%) harbored potentially pathogenic mutations in KCND3. The novel p.Val392Ile, p.Ser530Pro, and p.Gly600Arg mutations involved highly conserved residues and were absent in 1,560 reference alleles. Although the SIDS-associated p.Ser530Pro mutation demonstrated a wild-type (WT) electrophysiological phenotype when heterologously expressed, the SUDS-associated p.Val392Ile and p.Gly600Arg mutations significantly increased peak current density at +40 mV in comparison with WT by 100.4% (P < 0.05) and 50.4% (P < 0.05), respectively. p.Val392Ile also slowed recovery from inactivation 3.6-fold, indicating a mixed electrophysiological phenotype. This is the first report indicating that KCND3 may serve as a rare genetic substrate in the pathogenesis of SUDS but not SIDS cases.

MeSH terms

  • Action Potentials
  • Adolescent
  • Adult
  • Aged
  • Amino Acid Sequence
  • Amino Acid Substitution
  • Autopsy
  • Cell Line
  • Child
  • Child, Preschool
  • Cohort Studies
  • Death, Sudden, Cardiac / epidemiology
  • Death, Sudden, Cardiac / etiology*
  • Female
  • Humans
  • Infant
  • Male
  • Middle Aged
  • Mutation*
  • Prevalence
  • Shal Potassium Channels / genetics*
  • Shal Potassium Channels / metabolism
  • Sudden Infant Death / diagnosis
  • Sudden Infant Death / epidemiology
  • Sudden Infant Death / genetics*
  • Young Adult


  • Shal Potassium Channels