Table 1 Main characteristics of all studies included in the meta-analysis
AuthorYearCountry/ ethnicityDisease categoriesAge (controls)Genotyping methodSample size (case/control)CasesControlsP HWENOS score
CCCTTTCCCTTT
-397T/C: PvuII restriction site (rs2234693)
Severe pre-eclampsia
Salimi S.2017IranSevere26.5 ± 6.3PCR-RFLP192/186926154294500.867
El-Beshbishy H.A.2015SaudiNA24 ± 2.9PCR-RFLP97/942152242044300.617
Groten T.2014CaucasianSevereNAPCR27/175514143774640.087
Groten T.2014AfricanSevereNAPCR16/13431032478320.057
Zhang J.2009Chinese HanSevere28.71 ± 3.60PCR140/23648662678113450.728
Molvarec A.2006CaucasianSevere28 (25–31)PCR119/1032656371853320.628
Tempfer C.B.2004CaucasianSevere29 (21–43)PCR24/24414641280.897
Mild pre-eclampsia
Salimi S.2017IranMild26.5 ± 6.3PCR-RFLP142/1862881334294500.867
El-Beshbishy H.A.2015SaudiNA24 ± 2.9PCR-RFLP97/942152242044300.617
Groten T.2014CaucasianMildNAPCR47/175828283774640.087
Groten T.2014AfricanMildNAPCR65/131635142478320.057
Zhang J.2009Chinese HanMild28.71 ± 3.60PCR64/23624281278113450.728
AuthorYearCountryAge (cases)Genotyping methodSample size (case/control)CasesControlsP HWENOS score
GGAGAAGGAGAA
-351A/G: XbaI restriction site (rs9340799)
Severe pre-eclampsia
Salimi S.2017IranSevere26.5 ± 6.3PCR-RFLP192/1861417191998690.067
El-Beshbishy H.A.2015SaudiNA24 ± 2.9PCR-RFLP97/941354301058260.017
Molvarec A.2006CaucasianSevere28 (25–31)PCR119/1031962381464250.0098
Zhang J.2009Chinese HanSevere28.71 ± 3.60PCR140/236751828771510.638
Mild pre-eclampsia
Salimi S.2017IranMild26.5 ± 6.3PCR-RFLP142/1861382471998690.067
El-Beshbishy H.A.2015SaudiNA24 ± 2.9PCR-RFLP97/941354301058260.017
Zhang J.2009Chinese HanMild28.71 ± 3.60PCR64/236325368771510.638
  • Abbreviations: NA, not available; RFLP-PCR, restriction fragment length polymorphism PCR.