title: Genetic variation in the inwardly rectifying K channel subunits KCNJ3 (GIRK1) and KCNJ5 (GIRK4) in patients with sinus node dysfunction.
abstract: BACKGROUND
  Sinus node dysfunction (SND) is a heterogeneous disorder of unknown etiology characterized by a variety of supraventricular arrhythmias with symptoms of syncope, palpitations, and dizziness. The mechanism underlying the abnormal rhythm is incompletely understood.
  
  
  OBJECTIVE
  Because vagal stimulation and acetylcholine (ACh) affect the function of pacemaker cells, we hypothesized that genetic variation in the genes encoding the ACh-activated K(+) channels, the KACh channels, could be involved in the pathogenesis of SND.
  
  
  RESULTS
  We screened 184 patients listed in the pacemaker registry of the Copenhagen University Hospital aged <60 years at pacemaker implantation for SND in the period 1982-2005. Forty-three patients fulfilled the following inclusion criteria: documented sinus arrest, asystole, or extreme sinus bradycardia. The coding sequences of KCNJ3 and KCNJ5, encoding the main subunits of the KACh channels, were re-sequenced. We identified several known single nucleotide polymorphisms in KCNJ3 and KCNJ5, but no mutations in either of the genes.
  
  
  CONCLUSIONS
  Genetic variation in KCNJ3 and KCNJ5 encoding the subunits of the KACh channels is apparently not involved in the pathogenesis of SND.
authors.affiliation: Laboratory of Molecular Cardiology, Copenhagen University Hospital, Copenhagen, Denmark.
authors.forename: Haya N
authors.initials: HN
authors.lastname: Holmegard
authors.forename: Juliane
authors.initials: J
authors.lastname: Theilade
authors.forename: Marianne
authors.initials: M
authors.lastname: Benn
authors.forename: Morten
authors.initials: M
authors.lastname: Duno
authors.forename: Stig
authors.initials: S
authors.lastname: Haunso
authors.forename: Jesper H
authors.initials: JH
authors.lastname: Svendsen
mesh_terms: D000293:Adolescent; D000328:Adult; D000368:Aged; D000483:Alleles; D019943:Amino Acid Substitution / Q000235:genetics; D004252:DNA Mutational Analysis; D005260:Female; D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels / Q000235:genetics*; D005838:Genotype; D006801:Humans; D008297:Male; D008875:Middle Aged; D010138:Pacemaker, Artificial; D011110:Polymorphism, Genetic / Q000235:genetics*; D020641:Polymorphism, Single Nucleotide / Q000235:genetics; D012016:Reference Values; D017422:Sequence Analysis, DNA; D012804:Sick Sinus Syndrome / Q000175:diagnosis / Q000235:genetics* / Q000628:therapy; D055815:Young Adult
chemical_list: D051676:G Protein-Coupled Inwardly-Rectifying Potassium Channels; C497066:KCNJ3 protein, human; C484274:KCNJ5 protein, human