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ORPHA:168598

Methionine adenosyltransferase I/III deficiency

low confidenceDisorder

Also known as: MAT I/III deficiency · Mudd's disease

Publications

1,683

Trials

1

Interventional, condition-specific

Researchers

1,290

Distinct authors in sample

Gene link

MAT1A

Definitive

Readiness

4/6

Stages with a signal

Clinical definition (Orphanet)

A rare inborn error of metabolism characterized by persistently elevated serum methionine levels. Half of patients reported with MAT I/III deficiency, notably those with hypermethioninemia below 800 µM, have no CNS abnormalities and are clinically asymptomatic. However, individuals with higher levels might show evidence of central nervous system abnormalities, most notably hypo- or demyelination on brain MRI, as well as and . Bad breath or a strong smell of urine and sweat may be noted in some patients.

How rare: <1 / 1 000 000 — fewer than one in a million. In a city the size of Kolkata, that might mean on the order of fifteen people.

Orphanet entry

Cross-references

Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.

Additional Mondo synonyms (6)

MAT deficiency · brain demyelination due to methionine adenosyltransferase deficiency · hypermethioninemia, persistent, autosomal dominant, due to methionine adenosyltransferase I/III deficiency · isolated persistent hypermethioninemia · methionine adenosyltransferase deficiency · methionine adenosyltransferase deficiency, autosomal recessive

Research stages

Trial readiness signals

Where this condition sits on an open-data research pipeline — not how close a treatment is, and not medical advice. Empty stages often mean “not in these databases under this Mondo ID,” not “impossible.”

4/6 stages with a signal

An interventional trial matched this condition name on ClinicalTrials.gov — see trials below.

  1. Gene identifiedPresent

    Definitive — MAT1A

  2. LiteraturePresent

    1,683 matched papers (1,111 in last 10 years) Source

  3. Phenotype characterisedPresent

    7 HPO annotations (e.g. Hypermethioninemia; Peripheral demyelination; Dystonia) Source

  4. Animal modelNot found

    No Alliance genotype “model of” associations via Monarch for these Mondo IDs

  5. Orphan designationNot found

    No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source

  6. Interventional trialPresent

    1 matched on ClinicalTrials.gov

Biology

Genes and phenotypes

Gene–disease validity from GenCC, plus phenotypes and animal models joined from Monarch Initiative via Mondo ID — not a clinical diagnosis aid.

Do we know what causes it?

Yes — we know a specific gene responsible (MAT1A).

GenCC classification: Definitive.

Phenotypes (Monarch / HPO)

7

Associated phenotypes · MONDO:0009607

  • Hypermethioninemia
  • Peripheral demyelination
  • Dystonia
  • Halitosis
  • CNS demyelination

Showing 5 of 7 — open Monarch for the full list.

Animal models (Monarch / Alliance)

None returned for this Mondo ID. Empty here is not proof that no model organism work exists under another name or gene.

Monarch fetch 2026-07-29

Therapies

Designations, candidates, and chemicals

FDA OOPD and EMA orphan designations, Open Targets clinical candidates, and CTD chemical associations via MyDisease.info. These never change the interventional-trial headline.

Orphan designation (FDA · EMA)

No designation matched this disease via UMLS or preferred name on the FDA OOPD mirror or EMA orphan register. Absence here is not proof that none exists under another wording.

Open Targets candidates

1

Drugs / clinical candidates · MONDO_0009607

CTD chemicals (MyDisease.info)

No CTD chemical associations returned for this Mondo ID.

Literature

Is anyone studying this?

1,683

1,683 papers have been published on this condition. That is a real research literature — still far smaller than common diseases (breast cancer: over 700,000 papers). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.

1,683 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 59 (publications denominator n=3967).

1,111 in the last 10 years · low confidence

Phrase hits: 205 · MeSH hits: 0

Open Europe PMC search

Who's working on it?

1,290

Distinct author names in 200 sampled papers — named people below.

Who's working on it?

People publishing on this condition (sampled Europe PMC records). Affiliation is the most recent found in that sample.

  1. 01
    Mudd SH20 papers · 2015

    Laboratory of Molecular Biology, National Institute of Mental Health, Bethesda, MD 20892, USA. muddh@mail.nih.gov

    Papers in Europe PMC
  2. 02
    Blom HJ11 papers · 2020

    Laboratory of Clinical Biochemistry and Metabolism, Department of General Pediatrics, Adolescent Medicine and Neonatology, University Medical Centre Freiburg, Freiburg im Breisgau, Germany.

    Papers in Europe PMC
  3. 03
    Allen RH8 papers · 2017

    Division of Hematology, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Avenue, Room 9122, Bldg. RC2, Campus Box B170, Aurora, CO, USA.

    Papers in Europe PMC
  4. 04
    Couce ML7 papers · 2024

    Unidad de Trastornos Metabólicos, Departamento de Pediatría, Hospital Clínico Universitario, Santiago de Compostela, Spain.

    Papers in Europe PMC
  5. 05
    Tangerman A7 papers · 2018

    Department of Internal Medicine, RUNMC, Nijmegen, The Netherlands.

    Papers in Europe PMC
  6. 06
    Wagner C7 papers · 2015

    Department of Biochemistry, Vanderbilt University School of Medicine, Nashville, Tn, USA.

    Papers in Europe PMC
  7. 07
    Kožich V6 papers · 2021

    Institute of Inherited Metabolic Disorders, Charles University in Prague-First Faculty of Medicine and General University Hospital in Prague, Prague, Czech Republic.

    Papers in Europe PMC
  8. 08
    Levy HL6 papers · 2003
    Papers in Europe PMC
  9. 09
    Stabler SP6 papers · 2017

    Division of Hematology, Department of Medicine, University of Colorado School of Medicine, 12700 E. 19th Avenue, Room 9122, Bldg. RC2, Campus Box B170, Aurora, CO, USA. Sally.Stabler@ucdenver.edu.

    Papers in Europe PMC
  10. 10
    Zhang Y6 papers · 2024

    Department of Neurology, Beijing Friendship Hospital, Capital Medical University, Beijing, China.

    Papers in Europe PMC

Clinical research

Is a treatment being tested?

1

interventional trials for this specific condition

1 interventional trial matched this specific condition name; none in our sample are currently recruiting.

Data as of 11 September 2026 · last trial check 28 July 2026

1 interventional trial — more than 77.2% of diseases in the trials denominator have none at all (5501 of 7126; this disease is at the 80.1th percentile).

low confidence · 80.1th percentile (trials denominator)

Recruiting interventional trials

From the matched ClinicalTrials.gov set

1 interventional trials matched after quoted-phrase search and title/condition post-filter.

No currently recruiting studies in the matched set. Open the same search on ClinicalTrials.gov.

Other registries (secondary)

Broader net from EU CTIS, ISRCTN, and ICTRP when available — deduped against ClinicalTrials.gov IDs already counted above. Dual-model LLM relevance gates what we keep. These rows are not added to the interventional headline.

raw 0 · after dedupe 0 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 0 · dropped 0 · fetched 2026-07-30

Source notes: ictrp: Error: ICTRP public search unavailable (WHO portal is SPA-only; SOAP needs partnership). Tried: https://apps.who.int/tri

No secondary-registry studies passed dual-model relevance for this condition name (after dedupe).

Where to find support

Condition-specific patient organisations, when Orphanet lists them, are on the disease’s Orphanet page. We also link umbrella groups that support undiagnosed and ultra-rare families.

Orphanet entry for Methionine adenosyltransferase I/III deficiency — check Associations / patient organisations on that page.

India — NPRD

Last verified 2026-07-26

This ORPHAcode is not on our curated NPRD list (direct or Mondo-parent match). That does not decide clinical eligibility; families in India should ask a notified Centre of Excellence about current coverage.

Hand-curated for this project. ORPHAcode mappings are best-effort and may be incomplete or imprecise for umbrella categories. Parent (Mondo) matches mean the policy lists a broader category — confirm eligibility with a Centre of Excellence. Financial entitlements summarised from public policy statements and may change. This is not official government guidance.

How we counted this

Europe PMC query (preferred label + any corrected label + Orphanet and Mondo exact synonyms, stoplisted; unioned with resolved MeSH labels when available). UMLS / OMIM / NCIT cross-references are stored on the overview but are not added to the query string.

("Methionine adenosyltransferase I/III deficiency" OR "MAT I/III deficiency" OR "Mudd's disease" OR "MAT deficiency" OR "brain demyelination due to methionine adenosyltransferase deficiency" OR "hypermethioninemia, persistent, autosomal dominant, due to methionine adenosyltransferase I/III deficiency" OR "isolated persistent hypermethioninemia" OR "methionine adenosyltransferase deficiency" OR "methionine adenosyltransferase deficiency, autosomal recessive") OR ("MAT1A" OR "MAT1A syndrome" OR "MAT1A-related")

Run this search on Europe PMC

ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):

"Methionine adenosyltransferase I/III deficiency" OR "MAT I/III deficiency" OR "Mudd's disease" OR "MAT deficiency" OR "brain demyelination due to methionine adenosyltransferase deficiency" OR "hypermethioninemia, persistent, autosomal dominant, due to methionine adenosyltransferase I/III deficiency" OR "isolated persistent hypermethioninemia" OR "methionine adenosyltransferase deficiency" OR "methionine adenosyltransferase deficiency, autosomal recessive"

Interventional trials matched via: phrase (mesh = registered under a MeSH descriptor no name phrase would catch; recall-expansion = gene / selected parent terms used only for trials).

Study-type breakdown: 1 interventional · 0 observational · 0 expanded access. Only interventional studies enter the trial headline.

Query health: ok — strategies attempted: phrase; with hits: phrase

Run this search on ClinicalTrials.gov

Confidence reasoning

  • Preferred label is multi-word and distinctive
  • No synonyms dropped by stoplist
  • No label/synonym collisions with other diseases in this corpus
  • Publication count (1683) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity

Ingested 2026-07-27T08:28:49.501Z