GENETIC REGULATION OF THE METABOLISM OF METHIONINE, HOMOCYSTEINE AND VITAMINS В9, В12 IN CHILDREN LIVING NEAR THE CHERNOBYL EXCLUSION ZONE

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In 2015, the majority of children living near the Chernobyl exclusion zone had an elevated level of homocysteine in the blood, however, at the same time, the level of serum vitamins B9 and B12 was determined within the reference values. Considering that B vitamins are cofactors of the folate cycle enzymes that regulate the metabolism of the sulfur-containing amino acids methionine and homocysteine, it was important to determine the causes of this phenomenon. The purpose of this study was to identify correlations between vitamins В12, В9 and homocysteine, as well as vitamin В6, taking into account the genetic factor, in a group of children living under constant radiation exposure associated with the Chernobyl nuclear power plant accident. Research methods. The results of laboratory and instrumental examination of 178 children aged 12-17 from the Ivankovsky district of the Kyiv region were used. Immunochemical, genetic, spectrometric and statistical research methods were used. Results. Correlation analysis was used to study the relationship between the levels of homocysteine, B12, B9, B6 in the blood of children, taking into account their genetic status of folate cycle and the content of 137Cs in the body. An elevated level of homocysteine (more than 10.0 μmol/l) was detected in 73.0 % of the examined patients. The causes of hyperhomocysteinemia in children living near the Chernobyl exclusion zone are mutations in the folate cycle genes, insufficient content of vitamins B9 and B12 in the body, as well as the impact of an environmental factor associated with the Chernobyl nuclear power plant accident. The pathogenesis of the development of hyperhomocysteinemia in various variants of folate cycle genotypes is presented in detail. Conclusions. In assessing vitamins В9 and B12 status in children living near the Chernobyl exclusion zone, one should take into account not only their blood values but also that of homocysteine and vitamin В6, the specific activity of radionuclides in the body and the state of the genetic apparatus of the folate cycle. Despite the fact that homocysteine impaired remethylation processes occurred in most children living near the Chernobyl exclusion zone, the correction of their metabolism with vitamins В9 and B12 should be carried out individually, taking into account the state of the genes that control the folate cycle.