Neurologic Disease and Vitamin B₁₂ Levels in Children

Introduction: Vitamin B₁₂ deficiency is a well-known cause of neurologic symptoms, prompting routine measurement in patients with neurologic conditions. However, elevated B₁₂ levels are also observed in some cases. Recent studies suggest a potential link between high B₁₂ levels and neurologic or neurodevelopmental disorders. This study aims to evaluate vitamin B₁₂ levels in children with neurologic disorders compared with those in general pediatric populations. Materials and Methods: This single-center retrospective study analyzed pediatric patients' vitamin B₁₂ levels between 2000 and 2023. Exclusion criteria included incomplete data and vitamin supplementation. Patients were grouped based on B₁₂ levels (<200 pg/mL, 201-660 pg/mL, 661-1000 pg/mL, > 1000 pg/mL). Age, gender, and diagnoses were assessed, focusing on patients with elevated B₁₂ levels (>660 pg/mL) in the neurology clinic. Vitamin B₁₂ levels were measured using Roche Cobas e 601 analyzers. Results: Over 3 years, 4142 pediatric clinic and 2638 pediatric neurology patients were reviewed. Elevated B₁₂ levels were more frequent in the neurology clinic. Patients with elevated B₁₂ levels (n = 338) had a mean age of 8.67 months and a mean B₁₂ level of 894.7 pg/mL. Of 137 patients with follow-up B₁₂ measurements, 40.1% normalized, while 17.5% remained > 1000 pg/mL. The most common diagnosis in patients with persistently high B₁₂ levels was epilepsy, followed by prematurity, cerebral palsy, autism, intellectual disability, and language delay. Conclusions: Elevated vitamin B₁₂ levels were associated with pediatric neurologic disorders, particularly epilepsy. Further research is needed to clarify the mechanisms and clinical implications of this finding.