Disorders of vitamin B9 and B12 metabolism in children: prevalence, selected clinical aspects, and optimization of diagnostic approaches
Year: 2026
Type: article
Study design: Observational Study
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.
Source: Medicni perspektivi
Institution: Ivano-Frankivsk National Medical University
Language: English
Subfield: Nutrition and Dietetics
Field: Nursing
Domain: Health Sciences
Open Access status: diamond
OpenAlex ID: W7223576045