title: The GNB3 C825T polymorphism and essential hypertension: a meta-analysis of 34 studies including 14,094 cases and 17,760 controls.
abstract: OBJECTIVE
  The C825T single nucleotide polymorphism of the G-protein beta3 (GNB3) has been implicated in susceptibility to essential hypertension, through the expression of an alternatively spliced truncated variant. In an effort to clarify earlier inconclusive results, we performed a meta-analysis of population-based case-control genetic association studies.
  
  
  METHODS
  Random-effects methods were applied on summary data in order to combine the results of the individual studies.
  
  
  RESULTS
  We identified in total 34 studies, including 14,094 hypertensive cases and 17,760 controls. The TT versus CC + CT contrast yielded an overall odds ratio (OR) of 1.08 [95% confidence interval (CI): 1.01, 1.15], the contrast of TT + CT versus CC, an OR of 1.17 (95% CI: 1.06, 1.29), whereas that of the T allele versus C allele yielded a non-significant OR of 1.05 (95% CI: 0.98, 1.13). There was moderate evidence for a publication bias in the latter two contrasts, which was eliminated after excluding studies not in Hardy-Weinberg equilibrium and those performed on non-normal populations (those with a diagnosis of diabetes, obesity and myocardial infarction). Subgroup analyses revealed that non-significant estimates arose from studies on Asian populations, as opposed to the Caucasian ones. Furthermore, the frequency of the T allele was lower in Caucasians and these populations were found to inhabit higher latitudes.
  
  
  CONCLUSIONS
  The findings are in agreement with a recently proposed causal model for systolic blood pressure, which correlates it with the T allele and the absolute latitude. Further studies are needed in order to fully address questions about the aetiological mechanism of the particular association, as well as to study the effect in populations of African descent.
authors.affiliation: Department of Cell Biology and Biophysics, Faculty of Biology, University of Athens, Panepistimiopolis, Athens, Greece. pbagos@biol.uoa.gr
authors.forename: Pantelis G
authors.initials: PG
authors.lastname: Bagos
authors.forename: Antigoni L
authors.initials: AL
authors.lastname: Elefsinioti
authors.forename: Georgios K
authors.initials: GK
authors.lastname: Nikolopoulos
authors.forename: Stavros J
authors.initials: SJ
authors.lastname: Hamodrakas
mesh_terms: D001794:Blood Pressure / Q000235:genetics; D016022:Case-Control Studies; D044387:GTP-Binding Protein beta Subunits / Q000235:genetics*; D005838:Genotype; D006801:Humans; D006973:Hypertension / Q000235:genetics*; D016017:Odds Ratio; D020641:Polymorphism, Single Nucleotide; D012044:Regression Analysis; D044465:White People / Q000235:genetics
chemical_list: D044387:GTP-Binding Protein beta Subunits