{
  "abstract": "Disorders of vitamin B9 and B12 metabolism is an important problem in modern pediatrics due to its prevalence, nonspecific clinical manifestations, and diagnostic difficulties. Aim – to evaluate the prevalence and features of vitamin B9 and B12 metabolic disorders in school-aged children, to assess the role of hyper­homocysteinemia in clinical manifestations, and to improve diagnostic approaches. We analyzed 100 scientific publications (70% PubMed and Google Scholar) and examined 84 children aged 6-16 years observed at Ivano-Frankivsk Regional Children’s Clinical Hospital (59.5%) and the medical center “Doctor Tsaruk” (40.5%) during 2023-2026. Serum concen­trations of vitamins B9 and B12 were determined using enzyme-linked immunosorbent assay, plasma homocysteine con­centration was measured by high-performance liquid chromatography, and MTHFR C677T and MTRR A66G polymor­phisms were analyzed using polymerase chain reaction. Cognitive status was assessed using a Likert-scale questionnaire developed by the authors. Vitamin B12 and B9 deficiency in Ukraine ranges from 13.5-18.9%. The main clinical features were fatigue (85.7%) and weakness (77.4%). Cognitive disorders were significantly more frequent in children aged 6-12 years than in adolescents (93.1% vs 25.0%; χ²=34.8; p<0.0001). Adolescents more often reported memory impairment (54.5%) and reduced attention (45.4%). Isolated vitamin B12 deficiency was found in 54.8% of children, vitamin B9 deficiency – in 29.7%, and combined deficiency – in 13%. Mean corpuscular volume was higher in the combined deficiency group (104.8±7.1 fL), indicating macrocytic changes. Methylmalonic acid levels were increased in B12-deficient and combi­ned groups. The MTHFR C677T homozygous variant was associated with higher homocysteine levels (r=0.64; p<0.0. Chil­dren with combined deficiency showed significantly worse cognitive perfor­mance than those with isolated deficiency (p<0.05). Thus, Vitamin B9 and B12 deficiency is an important risk factor for cognitive impairment in children. Combined deficiency has a more severe clinical impact which underscores the need for early diagnosis and the consideration of genetic factors. A pathogenetically grounded approach makes it possible to improve treatment outcomes and the prevention of neurological complications.",
  "abstract_shown": true,
  "affiliations": [
    "Ivano-Frankivsk National Medical University, Halytska str., 2, Ivano-Frankivsk, 76018"
  ],
  "article_type": null,
  "arxiv": null,
  "author_total": 7,
  "authors": [
    {
      "affs": [
        0
      ],
      "name": "I.S. Lembryk",
      "orcid": "0000-0001-7584-7407"
    },
    {
      "affs": [
        0
      ],
      "name": "T.V. Shatynska",
      "orcid": "0009-0002-9932-0145"
    },
    {
      "affs": [
        0
      ],
      "name": "H.M. Dutchak",
      "orcid": "0000-0002-5514-498X"
    },
    {
      "affs": [
        0
      ],
      "name": "V.M. Voloshynovych",
      "orcid": "0000-0002-7326-8513"
    },
    {
      "affs": [
        0
      ],
      "name": "O.V. Tymoshchuk",
      "orcid": "0000-0002-7225-0725"
    },
    {
      "affs": [
        0
      ],
      "name": "O.I. Dmyterko",
      "orcid": "0009-0006-7549-8618"
    },
    {
      "affs": [
        0
      ],
      "name": "N.O. Rumezhak",
      "orcid": "0009-0007-1314-7940"
    }
  ],
  "bibtex": "https://research.draconitic.com/paper/f4sxga0t1f983.bib",
  "cited_by": 0,
  "doi": "10.26641/2307-0404.2026.3.376300",
  "fulltext_url": "https://journals.uran.ua/index.php/2307-0404/article/view/376300",
  "id": "f4sxga0t1f983",
  "issns": [
    "2307-0404",
    "2786-4804"
  ],
  "landing_url": "https://doi.org/10.26641/2307-0404.2026.3.376300",
  "language": "en",
  "licence": "CC-BY",
  "licence_label": "CC BY",
  "licence_source": "journal",
  "licence_url": "https://creativecommons.org/licenses/by/4.0/",
  "metadata_licence": null,
  "native_subjects": [
    [
      "lcc",
      "R"
    ],
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      "openalex",
      "2745|Folate and B Vitamins Research"
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  "openalex": "W7223576045",
  "pdf_url": "https://journals.uran.ua/index.php/2307-0404/article/download/376300/359768",
  "pmcid": null,
  "pmid": null,
  "published": "2026-09-01",
  "publisher": "Dnipro State Medical University",
  "ris": "https://research.draconitic.com/paper/f4sxga0t1f983.ris",
  "sources": [
    {
      "first_seen": "2026-10-30T13:44:08Z",
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      "url": "https://doi.org/10.26641/2307-0404.2026.3.376300"
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  "subjects": [
    {
      "field": "medicine",
      "origin": "openalex:2745|Folate and B Vitamins Research",
      "subfield": "general"
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  ],
  "title": "Disorders of vitamin B9 and B12 metabolism in children: prevalence, selected clinical aspects, and optimization of diagnostic approaches",
  "title_text": "Disorders of vitamin B9 and B12 metabolism in children: prevalence, selected clinical aspects, and optimization of diagnostic approaches",
  "type": "peer-reviewed",
  "updated_at": "2026-10-30T13:44:08Z",
  "url": "https://research.draconitic.com/paper/f4sxga0t1f983",
  "venue": "Medičnì Perspektivi",
  "versions": []
}