Living with Glycine N-methyltransferase deficiency
A very rare condition with lasting high methionine levels in the blood, a slightly enlarged liver, and no liver disease.
Understanding Glycine N-methyltransferase deficiency
The only clinical changes are a mild increase in liver size and long-lasting high liver enzyme (transaminase) levels in the blood, without liver disease. Methionine may also be raised in urine. High methionine is a risk factor for neurological problems, which can occur when methionine levels are above 800 μmol/L.
Signs & symptoms
GARD doesn't list a symptom list for this condition. The summary describes these:
- High methionine in the blood (hypermethioninemia)
- Mildly enlarged liver
- High liver enzyme levels without liver disease
Not everyone has every symptom. GARD's list comes from the Human Phenotype Ontology.
Diagnosis
- 1Talk with your doctor
Share the symptoms you've noticed, when they started and your family health history. Notes and photos can help.
- 2See a specialist
Specialists who may be involved include genetic specialists.
- 3Consider genetic testing
Changes in GNMT are linked to this condition. Genetic testing and counseling can help confirm a diagnosis and explain what it means for your family.
Care & treatment
- Care team
- Genetic specialists (geneticists)
- Expert care
- Ask about multidisciplinary care centers for rare conditions
- Treatment
- GARD doesn't list specific treatments for this condition. Your care team will tailor care to your symptoms.
- Research
- Clinical trials and observational studies may be options. See the research section below.
General information, not medical advice. Your care team makes the decisions.
Everyday life
Living with a rare condition is easier with support.
- Connect with rare disease patient organizations for support
- Keep notes on symptoms, changes and questions for appointments
- Ask about patient registries that help research
- Look into financial aid and travel resources for care visits
Quick facts
Changes in the GNMT gene cause this condition. A child inherits a changed copy of the gene from each parent (autosomal recessive).
Also known as: gnmt deficiency; hypermethioninemia due to deficiency of glycine n-methyltransferase; hypermethioninemia due to glycine n-methyltransferase deficiency; hypermethioninemia due to gnmt (glycine n-methyltransferase) deficiency; hypermethioninemia due to gnmt deficiency
Patient organizations
Rare-disease groups that can help
- Global GenesRare Diseases · United States
- National Organization for Rare DisordersRare Diseases · United States
- Genetic AllianceRare Diseases · United States
- RARE FoundationRare Diseases · United States
You are more than your diagnosis
Perspectives from people navigating life with Glycine N-methyltransferase deficiency.
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