title: The role of the sodium current complex in a nonreferred nationwide cohort of sudden infant death syndrome.
abstract: BACKGROUND
  Sudden infant death syndrome (SIDS) is the most common cause of death in infants between the age of 1 month and 1 year. Rare variants in Nav1.5 encoded by SCN5A are known to play a role in SIDS; however, the combined role of the sodium current complex is unknown.
  
  
  OBJECTIVE
  The purpose of this study was to investigate the role of the sodium current complex in a nonreferred nationwide cohort of SIDS cases.
  
  
  METHODS
  DNA was extracted from dried blood spot samples from the Danish Neonatal Screening Biobank. In total, 66 non-referred SIDS cases born in Denmark in the period of 2000-2006 were screened for genetic variants in the 8 major genes involved in the regulation of the Nav1.5 channel complex: SCN5A, SCN1B, SCN2B, SCN3B, SCN4B, GPD1L, SNTA1, and CAV3. Patch-clamp analyses were performed on variants not previously characterized.
  
  
  RESULTS
  In total, 8 patients (12%) had nonsynonymous rare variants in the sodium current genes. SCN5A harbored 6 rare variants (R458C, R535*, S1103Y, R1193Q, S1609L, and Q1909R); CAV3, 1 rare variant (T78M); GPD1L, 1 rare variant (R220H); and SCN3B, 1 rare variant (L10P). Four variants were considered likely pathogenic and 5 variants of unknown significance. SCN5A R1193Q and GPD1L R220H (both considered variants of unknown significance) were present in the same infant. Functional analysis of variants not previously characterized (R458C, S1609L, and Q1909R in SCN5A) predominantly revealed increased transient and sustained sodium current.
  
  
  CONCLUSIONS
  In a nonreferred nationwide Danish cohort of SIDS cases, up to 5/66 (7.5%) of SIDS cases can be explained by genetic variants in the sodium channel complex genes.
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark. Electronic address: bowinkel@dadlnet.dk.
authors.forename: Bo Gregers
authors.initials: BG
authors.lastname: Winkel
authors.affiliation: Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Lei
authors.initials: L
authors.lastname: Yuan
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Morten S
authors.initials: MS
authors.lastname: Olesen
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Golnaz
authors.initials: G
authors.lastname: Sadjadieh
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Yinman
authors.initials: Y
authors.lastname: Wang
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Bjarke
authors.initials: B
authors.lastname: Risgaard
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Reza
authors.initials: R
authors.lastname: Jabbari
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Stig
authors.initials: S
authors.lastname: Haunsø
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Anders Gaarsdal
authors.initials: AG
authors.lastname: Holst
authors.affiliation: Department of Clinical Biochemistry and Immunology, Danish Centre for Neonatal Screening, Statens Serum Institut, Copenhagen, Denmark.
authors.forename: Mads Vilhelm
authors.initials: MV
authors.lastname: Hollegaard
authors.affiliation: Department of Cardiology, Copenhagen University Hospital, Rigshospitalet, Copenhagen, Denmark; Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark.
authors.forename: Jacob
authors.initials: J
authors.lastname: Tfelt-Hansen
authors.affiliation: Danish National Research Foundation Centre for Cardiac Arrhythmia (DARC), University of Copenhagen, Copenhagen, Denmark; Department of Biomedical Sciences, University of Copenhagen, Copenhagen, Denmark.
authors.forename: Thomas
authors.initials: T
authors.lastname: Jespersen
mesh_terms: D003718:Denmark; D005260:Female; D014644:Genetic Variation; D006801:Humans; D007223:Infant; D007231:Infant, Newborn; D008297:Male; D015222:Sodium Channels / Q000235:genetics*; D013398:Sudden Infant Death / Q000235:genetics*
chemical_list: D015222:Sodium Channels