MTHFR 677TT: Clinical Relevance and DiagnosticLimitations‎: A Case Report

  • Authors

    • Siham Bahbouh University of Health Sciences - Faculty of Medicine of Algiers, Algeria
    • Roza Sahraoui Department of Neurology, Aït Idir Neurosurgical Hospital, Algiers, Algeria
    https://doi.org/10.14419/rx72ba46

    Received date: January 12, 2026

    Accepted date: March 28, 2026

    Published date: April 5, 2026

  • MTHFR 677TT; Folate Metabolism; Homocysteine; Atypical Psychiatric Disorders; Personalized ‎Medicine; Clinical Genetics

  • Abstract

    Introduction: The c.677C>T mutation of the MTHFR gene, in the homozygous state (677TT), leads to ‎reduced activity of methylenetetrahydrofolate reductase, a key enzyme in folate metabolism ‎and methylation reactions. Its clinical expression is heterogeneous and may manifest as ‎atypical psychiatric presentations, even in the absence of hyperhomocysteinemia, thereby ‎limiting the diagnostic value of standard biological markers.‎

    Methods: We report the case of a female patient presenting with atypical psychotic symptoms partially ‎resistant to conventional treatment. The biological workup was complemented by genetic ‎analysis, including genotyping of the MTHFR gene.‎

    Results: Genotyping revealed a homozygous MTHFR c.677C>T mutation. Targeted metabolic ‎management was initiated, based on supplementation with active folates (5-‎methyltetrahydrofolate) combined with vitamins B12 and B6, with biological monitoring. ‎A gradual clinical improvement was observed, allowing a reduction in antidepressant ‎treatment.‎

    Discussion/Conclusion: This case illustrates the value of MTHFR genotyping in identifying an underlying metabolic ‎vulnerability in patients presenting with atypical or treatment-resistant clinical features. The ‎clinical relevance of the 677TT genotype lies in an integrative and personalized approach, ‎while its diagnostic limitations require cautious and contextualized interpretation of genetic ‎findings.

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  • How to Cite

    Bahbouh , S., & Sahraoui , R. . (2026). MTHFR 677TT: Clinical Relevance and DiagnosticLimitations‎: A Case Report. International Journal of Medicine, 14(1), 31-35. https://doi.org/10.14419/rx72ba46