engleski

The effects of MT2A –209A/G gene polymorphism and maternal smoking habits on trace elements in mother-infant pairs

Metallothioneins (MTs) are a family of cysteine- rich metal-binding proteins with main functions in homeostasis of essential elements (especially Zn and Cu) and protection against metals toxicity. They also have a role in free radical scavenging and oxidative stress protection. In humans, of the four known MT isoforms, MT1 and MT2 are the most prevalent. However, MT2 synthesis seems predominantly induced by toxic metal ions. In the MT2A gene, 24 single nucleotide polymorphisms were identified, but only several were shown to affect physiological and pathophysiological processes as well as element levels in the body. The aim of this study was to assess genotype frequencies of MT2A –209A/G for the first time in Croatia (postpartum women, n = 401) and its effect on element levels in maternal blood, placenta and cord blood. PCR-RFLP was used for MT2A –209A/G genotyping and ICP-MS for trace element analysis. Results showed that 60.6 % of subjects were homozygous dominant (AA), 36.2 % heterozygous (AG), and 3.2 % homozygous recessive (GG). Maternal smoking increased Cd and Pb in all analysed samples, Fe and Cu in cord blood, and Zn in the placenta. In smokers, G allele carriers (AG/GG) vs. AA genotype had lower Cu in maternal blood and placenta and no differences were found for other elements. Maternal smoking habit affected element levels in all compartments of maternal-placental-foetal unit, however, effect of MT2A –209A/G polymorphism on trace element levels should be further explored in a larger population. This study was funded by the Croatian Science Foundation (grant HRZZ-IP-2016-06-1998).

single nucleotide polymorphism ; maternal blood ; placenta ; umbilical cord blood ; metallothioneins

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