title: Gene Polymorphism of the Adenosine A2a Receptor in Patients with Vasovagal Syncope.
abstract: BACKGROUND
  Adenosine may play a role in the pathogenesis of vasovagal syncope (VVS). The aim of the study was to evaluate the adenosine A(2A) receptor gene 1083 T > C polymorphism in patients with syncope and its possible association with results of head-up tilt test (HUT).
  
  
  METHODS
  Three hundred and forty-seven consecutive patients (mean age 47.3 ± 18.5 years, 132 men, 215 women) with one or more syncopal episodes underwent HUT as part of standardized diagnostic evaluation. HUT was positive in 207 patients (75 males, mean age 44.7 ± 18.6 years) and negative in 140 patients (58 males, mean age 48.17 ± 18.8 years). One thousand and eighty-three T > C single nucleotide polymorphism in the adenosine A(2A) receptor gene (rs5751876) was evaluated in 347 patients with syncope and in 85 subjects without history of syncope (54 men, mean age 41.7 ± 16.3).
  
  
  RESULTS
  Adenosine A(2A) receptor 1083 T > C polymorphism was not associated with the positivity of HUT. Blood pressure and heart rate response to tilting was similar in all genotypes. Low frequency (LF) power was significantly lower in CC genotype compared to CT genotype in early phase of tilt (log LF 2.69 ± 0.61 vs 3.20 ± 0.60; P = 0.01) and at the time of syncope (log LF 2.60 ± 0.63 vs 2.77 ± 0.48; P = 0.04).
  
  
  CONCLUSIONS
  Adenosine A(2A) receptor 1083 T > C polymorphism is not associated with the positivity of HUT and its proposed role in predisposition to VVS was not confirmed. CC genotype may be associated with lower sympathetic activity during HUT.
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Peter
authors.initials: P
authors.lastname: Mitro
authors.affiliation: Department of Medical Biology, Safarik University, Košice, Slovak Republic.
authors.forename: Viera
authors.initials: V
authors.lastname: Habalova
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Lukas
authors.initials: L
authors.lastname: Evin
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Ervin
authors.initials: E
authors.lastname: Muller
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Milos
authors.initials: M
authors.lastname: Simurda
authors.affiliation: Department of Medical Biology, Safarik University, Košice, Slovak Republic.
authors.forename: Eva
authors.initials: E
authors.lastname: Slaba
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Pavol
authors.initials: P
authors.lastname: Murin
authors.affiliation: Cardiology Clinic, Safarik University and VUSCH, Košice, Slovak Republic.
authors.forename: Gabriel
authors.initials: G
authors.lastname: Valocik
mesh_terms: D000328:Adult; D015415:Biomarkers; D005260:Female; D005819:Genetic Markers / Q000235:genetics; D020022:Genetic Predisposition to Disease / Q000453:epidemiology* / Q000235:genetics*; D006801:Humans; D008297:Male; D008875:Middle Aged; D020641:Polymorphism, Single Nucleotide / Q000235:genetics*; D015995:Prevalence; D043705:Receptor, Adenosine A2A / Q000235:genetics*; D012307:Risk Factors; D018154:Slovakia / Q000453:epidemiology; D019462:Syncope, Vasovagal / Q000175:diagnosis / Q000453:epidemiology* / Q000235:genetics*
chemical_list: D015415:Biomarkers; D005819:Genetic Markers; D043705:Receptor, Adenosine A2A
keywords: adenosine receptor; gene polymorphism; head-up tilt test; heart rate variability; vasovagal syncope