RESUMO
OBJECTIVE: Periconceptional folate supplementation prevents a number of congenital anomalies (CA). The aim of our study was to investigate the association of 11 polymorphisms in the folate-metabolizing genes with the risk of having an offspring with CA in the Russian ethnic group. METHOD: We genotyped 280 mothers having a CA-affected pregnancy and 390 control mothers. The most common malformations among the cases were CA of the nervous, urinary, and cardiovascular systems, and these groups were analyzed separately. RESULTS: In the whole group of CA, we revealed the associations of MTHFR C677T and MTR A2756G loci with increased risk of CA-affected pregnancy. In the group of CA of the cardiovascular system, we observed an association of MTHFR A1298C with decreased risk and an association of MTR A2756G with increased risk of CA. After the Bonferroni correction, only the association between the genotype MTR 2756GG and the risk of having a fetus with CA of the cardiovascular system remained statistically significant (OR = 4.99, P = 0.03). CONCLUSION: These findings indicate that locus A2756G in the MTR gene may play a role in susceptibility to CA of the cardiovascular system in West Siberia, but further research is necessary to confirm the association.
Assuntos
5-Metiltetra-Hidrofolato-Homocisteína S-Metiltransferase/genética , Anormalidades Congênitas/genética , Predisposição Genética para Doença , Metilenotetra-Hidrofolato Redutase (NADPH2)/genética , Polimorfismo de Nucleotídeo Único , Adulto , Anormalidades Cardiovasculares/epidemiologia , Anormalidades Cardiovasculares/genética , Anormalidades Cardiovasculares/metabolismo , Estudos de Casos e Controles , Anormalidades Congênitas/metabolismo , Feminino , Genótipo , Humanos , Malformações do Sistema Nervoso/epidemiologia , Malformações do Sistema Nervoso/genética , Malformações do Sistema Nervoso/metabolismo , Gravidez , Sibéria/epidemiologia , Anormalidades Urogenitais/epidemiologia , Anormalidades Urogenitais/genética , Anormalidades Urogenitais/metabolismoRESUMO
BACKGROUND: Periconceptional folic acid supplementation is widely believed to aid in the prevention of neural tube defects (NTDs), orofacial clefts, and congenital heart defects. Folate-binding proteins or receptors serve to bind folic acid and 5-methyltetrahydrofolate, representing one of the two major mechanisms of cellular folate uptake. METHODS: We herein describe abnormal cardiovascular development in mouse fetuses lacking a functional folate-binding protein gene (Folr1). We also performed a dose-response study with folinic acid and determined the impact of maternal folate supplementation on Folr1 nullizygous cardiac development. RESULTS: Partially rescued preterm Folr1(-/-) (formerly referred to as Folbp1) fetuses were found to have outflow tract defects, aortic arch artery abnormalities, and isolated dextracardia. Maternal supplementation with folinic acid rescued the embryonic lethality and the observed cardiovascular phenotypes in a dose-dependant manner. Maternal genotype exhibited significant impact on the rescue efficiency, suggesting an important role of in utero folate status in embryonic development. Abnormal heart looping was observed during early development of Folr1(-/-) embryos partially rescued by maternal folinic acid supplementation. Migration pattern of cardiac neural crest cells, genetic signals in pharyngeal arches, and the secondary heart field were also found to be affected in the mutant embryos. CONCLUSIONS: Our observations suggest that the beneficial effect of folic acid for congenital heart defects might be mediated via its impact on neural crest cells and by gene regulation of signaling pathways involved in the development of the pharyngeal arches and the secondary heart field.