Tier 2 — strong

First Revision of the Guidelines for the Diagnosis and Management of Remethylation Disorders

Giorgia Olivieri, Andrea Bordugo, Birute Burnyte, Alessandro Costetti, Maria-Luz Couce, Luisa Diogo, Francois Feillet, D Sean Froese, Benedetta Greco, Jean-Louis Gueant, Luciana Hannibal, Friederike Hörster, Viktor Kožich, Giancarlo La Marca, Irini Manoli, Fanny Mochel, Lorenzo Orazi, Belén Pérez, Manuel Schiff, Bernd C Schwahn, Ida Schwartz, Karolina M Stepien, Jolanta Sykut-Cegielska, Trine Tangeraas, Rolf H Zetterström, Carlo Dionisi-Vici, Martina Huemer
Journal of inherited metabolic disease 2026 49(4):e70177

Bibliography

PubMed
PMID 42231716
DOI
10.1002/jimd.70177
Funding
Indexed grant support: SSIEM; Associazione Italiana Acidemie metilmalonica con omocistinuria cblcAPS; Homocystinuria network australia. The indexed list may not contain the complete funding declaration.
Competing interests
A competing-interest declaration was not available in the indexed record or accessible disclosure metadata.

Study snapshot

DesignClinical practice guideline
ModelEvidence synthesis; mixed research models
SampleSystematic review, GRADE evaluation and Delphi consensus
InterventionDiagnosis-specific treatment of inherited remethylation disorders
DurationUpdated long-term management guidance
EndpointsRemethylation disorders; Early treatment; Monitoring targets

What the study showed, in plain terms

Published in 2026, this source examined prescription betaine and inherited metabolic disorders. Its evidence base was Systematic review, GRADE evaluation and Delphi consensus. It evaluated Diagnosis-specific treatment of inherited remethylation disorders across Updated long-term management guidance.

The revision emphasizes early diagnosis, betaine for severe MTHFR deficiency and parenteral hydroxocobalamin for cobalamin-related disorders.

High-quality trials remain scarce. Recommendations concern rare inherited diseases and cannot be converted into general TMG supplementation advice.

Continue with TMG Data Center

Continue with TMG, Methylation and MTHFR: Understanding the Evidence

Key findings

  • The revision emphasizes early diagnosis, betaine for severe MTHFR deficiency and parenteral hydroxocobalamin for cobalamin-related disorders.
  • The recorded outcome domains were Remethylation disorders; Early treatment; Monitoring targets.

What this study can and cannot tell us

  • High-quality trials remain scarce. Recommendations concern rare inherited diseases and cannot be converted into general TMG supplementation advice.
  • The conclusions inherit the limitations of the underlying studies. A narrative interpretation or guideline recommendation is not a new randomized treatment comparison.
  • Source basis: Indexed abstract and bibliographic data. Missing method details, funding information or participant denominators are not inferred.

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Citation network

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Editorial review

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Dr. Khaled Mahmoud, MBBChCritical Care Medicine, Longevity Science & Editorial Direction Dr. Amr Yasser, PhDCardiometabolic, Musculoskeletal, Gut & Bioavailability Dr. Abdulla Mostafa, PhDCellular Senescence, Neurological, Mitochondrial & Brain-Ageing Biology