AIM: Up to 20% of pregnancies end in the first trimester by spontaneous abortion but the cause of a large proportion remains unexplained. The aim of this study was to investigate the role of two common variants (rs1801133, C677T and rs1801131, A1298C) within the MTHFR gene in the genetic determination of spontaneous abortions. METHODS: DNA from 464 tissue samples of spontaneous abortions and population sample of adults (N=2,486) were genotyped for both MTHFR polymorphisms of interest. RESULTS: The frequencies of the MTHFR polymorphisms in tissues from spontaneous abortions did not differ from the population cohort. However, when combined, carriers of at least three rs1801133 and/or rs1801131 alleles were more common in the spontaneous abortions (61.4%) than in controls (55.4%) and this combination was associated with higher risk of abortion (OR 1.28; 95% CI 1.05-1.57; P=0.017). In contrast, carriers of at least three minor alleles (T677 and C1298) of these polymorphisms were very rare in both groups (0.8% and 0.9% respectively). CONCLUSIONS: Our study suggests that distinct combinations of the MTHFR polymorphisms could be associated with higher risk of spontaneous abortions in Caucasians.

Centre for Experimental Medicine Institute for Clinical and Experimental Medicine Prague Czech Republic

Department of Obstetrics and Gynecology 1st Faculty of Medicine and General University Hospital Prague Czech Republic

Department of Preventive Cardiology Institute for Clinical and Experimental Medicine Prague Czech Republic

Department of Surgery Penn Transplant Institute Perelman School of Medicine University of PA Philadelphia USA

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The role of connexin 37 polymorphism in spontaneous abortion