Methylenetetrahydrofolate Reductase (MTHFR) Gene C677T Polymorphism and Risk of Preeclampsia: An Updated Meta-analysis Based on 51 Studies

Background and AimsThe methylenetetrahydrofolate reductase (MTHFR) gene C677T polymorphism has been considered to be associated with preeclampsia (PE), but the results from previous studies were conflicting. The present study aimed at investigating the frequency of preeclampsia according to the distribution polymorphism using a meta-analysis on the published studies.MethodsThe English and Chinese databases were searched to identify eligible studies published in English before August 2012. Data were extracted using standardized methods. The association was assessed by odds ratio (OR) with 95% confidence intervals (CI). Begg's test was used to measure publication bias.ResultsA total of 51 case–control studies containing 6,403 patients and 11,346 controls were involved in this meta-analysis. Significant associations were detected between MTHFR C677T polymorphism and risk of PE in the overall population for TT vs. CC (OR = 1.280, 95% CI: 1.074–1.525), recessive model (OR = 1.264, 95% CI: 1.067–1.303), and dominant genetic model (OR = 1.174, 95% CI: 1.057–1.303); in Caucasian population for dominant model (OR = 1.136, 95% CI: 1.022–1.263), and in East Asia population for TT vs. CC (OR = 2.199, 95% CI: 1.366–3.924) CT vs. CC (OR = 1.453, 95% CI: 1.001–2.109), recessive model (OR = 1.742, 95% CI: 1.202–2.525), and dominant model (OR = 1.783, 95% CI: 1.271–2.501). Conversely, no associations were detected in Latin America, South Asia, and Africa populations.ConclusionsResults of the meta-analysis suggest that the MTHFR C677T polymorphism was associated with risk of PE in overall, Caucasian, and East Asia populations. Nevertheless, the results for Latino, East Asians, South Asians and Africans should be interpreted with caution due to the small sample size.