ORPHA:280183
Methylmalonic aciduria due to transcobalamin receptor defect
Also known as: Methylmalonic acidemia, TCb1R type · Methylmalonic acidemia, TCbIR type
Publications
9,562
Trials
0
Interventional, condition-specific
Researchers
48
Distinct authors in sample
Gene link
CD320
Definitive
Readiness
4/6
Stages with a signal
Clinical definition (Orphanet)
Methylmalonic aciduria due to transcobalamin receptor defect is a rare metabolite absorption and transport disorder characterized by a moderate increase of methylmalonic acid (MMA) in the blood and urine due to decreased cellular uptake of cobalamin resulting from decreased transcobalamin receptor function. Patients are usually asymptomatic however, screening reveals increased C3-acylcarnitine and MMA in plasma. Serum homocysteine levels may vary from normal to moderately elevated and retinal vascular occlusive disease, resulting in severe visual loss, has been reported.
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.
Cross-references
Joined from Mondo / Orphanet. MeSH labels may enter searches; UMLS / OMIM / NCIT are stored for reference.
- MONDO:0013341
- OMIM:613646
- UMLS:C4749905
Additional Mondo synonyms (5)
CD320 methylmalonic acidemia · methylmalonic acidemia caused by mutation in CD320 · methylmalonic acidemia, TCb1R type · methylmalonic acidemia, TCbIR type · methylmalonic aciduria due to transcobalamin receptor defect
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
No matched interventional trial, but a gene association and an animal model are on record — often described as translation-ready / stalled at the clinical step.
- Gene identifiedPresent
Definitive — CD320
- LiteraturePresent
9,562 matched papers (5,321 in last 10 years) Source
- Phenotype characterisedPresent
6 HPO annotations (e.g. Hyperhomocystinemia; Reduced cellular cobalamin uptake; Methylmalonic aciduria) Source
- Animal modelPresent
1 genotype model (Mus musculus) Source
- Orphan designationNot found
No FDA or EMA orphan-drug designation matched this disease via UMLS or preferred name Source
- Interventional trialNot found
No matched interventional trial under our ClinicalTrials.gov rules
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 (CD320).
GenCC classification: Definitive.
Phenotypes (Monarch / HPO)
6
Associated phenotypes · MONDO:0013341
- Hyperhomocystinemia
- Reduced cellular cobalamin uptake
- Methylmalonic aciduria
Showing 3 of 6 — open Monarch for the full list.
Animal models (Monarch / Alliance)
1
Model associations linked to this Mondo ID
- Cd320Gt(CC0426)Wtsi/Cd320Gt(CC0426)Wtsi [background:] involves: 129P2/OlaHsd * C57BL/6·MGI:5512998·Mus musculus
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
No drugs or clinical candidates returned for this Mondo ID on Open Targets.
CTD chemicals (MyDisease.info)
No CTD chemical associations returned for this Mondo ID.
Literature
Is anyone studying this?
9,562
9,562 papers — among the better-studied rare conditions, though still a fraction of common-disease literature (breast cancer: over 700,000). Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=3967) is 59.
9,562 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).
5,321 in the last 10 years · low confidence
Phrase hits: 4 · MeSH hits: 0
Who's working on it?
48
Distinct author names in 4 sampled papers — named people below.
Who's working on it?
No interventional trial matched this name; these authors publish on it in the sampled literature — a practical starting point for contact.
- 01Shukla PK2 papers · 2025
Department of Computer Science & Engineering , University Institute of Technology, Rajiv Gandhi Proudyogiki Vishwavidyalaya (State Technological University), Bhopal, Madhya Pradesh, India.
Papers in Europe PMC - 02Abugabah A1 paper · 2025
College of Technological Innovation, Zayed University, Abu Dhabi, United Arab Emirates.
Papers in Europe PMC - 03Alagia M1 paper · 2025
Department of Translational Medicine, University of Naples "Federico II", Naples, Italy.
Papers in Europe PMC - 04Albano L1 paper · 2025
CEINGE Advanced Biotechnologies Franco Salvatore, Naples, Italy.
Papers in Europe PMC - 05
- 06Awada H1 paper · 2025
UMRS Inserm 1256 nGERE (Nutrition-Genetics-Environmental Risks), Institute of Medical Research (Pôle BMS), University of Lorraine, Nancy, France.
Papers in Europe PMC - 07Barretta F1 paper · 2025
Department of Molecular Medicine and Medical Biotechnology, University of Naples "Federico II", Naples, Italy.
Papers in Europe PMC - 08Brunetti-Pierri N1 paper · 2025
Department of Translational Medicine, University of Naples "Federico II", Naples, Italy.
Papers in Europe PMC - 09Cacchiarelli D1 paper · 2025
Department of Translational Medicine, University of Naples "Federico II", Naples, Italy. davide.cacchiarelli@unina.it.
Papers in Europe PMC - 10
Clinical research
Is a treatment being tested?
0
interventional trials for this specific condition
No interventional trial testing a treatment matched this specific condition name on ClinicalTrials.gov (observational studies and pan-disease registries are listed separately when present).
Data as of 11 September 2026 · last trial check 11 September 2026
No matched interventional trials. This is true for 77.2% of diseases in the trials denominator (5501 of 7126). Here are the researchers publishing on it.
low confidence · 38.6th percentile (trials denominator)
Recruiting interventional trials
From the matched ClinicalTrials.gov set
No interventional trial testing a treatment was found for this specific condition name on ClinicalTrials.gov.
See who's working on it — people publishing on this disease are often the practical next contact when no trial is listed.
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 3 · after dedupe 3 · already on CT.gov 0 · kept 0 · parent 0 · uncertain 3 · 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).
Uncertain / not reviewed (3)
- ctis·2022-502910-10-00·Authorised, recruiting·A Global, Phase 1/2, Open-label, Dose Optimization Study to Evaluate the Safety, Pharmacodynamics, and Pharmacokinetics of mRNA-3927 in Participants with Propionic Acidemia
skipped — LLM skipped (--skip-llm)
- ctis·2022-502492-32-00·Cancelled·A Global, Phase 1/2 Study to Evaluate the Safety, Tolerability, Pharmacodynamics, and Pharmacokinetics of mRNA-3705 in Participants with Isolated Methylmalonic Acidemia Due to Methylmalonyl-CoA Mutase Deficiency
skipped — LLM skipped (--skip-llm)
- ctis·2022-501997-20-00·Authorised, ongoing·A Phase 1/2, Global, Open-Label, Extension Study to Evaluate the Long-Term Safety and Clinical Activity of mRNA-3705 in Participants Previously Enrolled in Other Clinical Studies of mRNA-3705.
skipped — LLM skipped (--skip-llm)
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 Methylmalonic aciduria due to transcobalamin receptor defect — check Associations / patient organisations on that page.
India — NPRD
Last verified 2026-07-26Likely covered — the policy lists Methylmalonic acidemia as a category (Group 2), and this condition is a form of it. Confirm eligibility with a Centre of Excellence.
Group 2 — long-term / lifelong lower-cost interventions
NPRD envisages State Government support for dietary formulae, hormones, and other lower-cost interventions. This is a different route from the central CoE ₹50 lakh pathway; ask your state health department and a CoE which channel applies.
Central CoE funding may also apply depending on current rules — confirm with a notified Centre of Excellence. Do not assume the ₹50 lakh ceiling covers Group 2 by default. Verify
Centres of Excellence (15)
- All India Institute of Medical Sciences (AIIMS) — New Delhi, Delhi
- Maulana Azad Medical College — New Delhi, Delhi
- Sanjay Gandhi Post Graduate Institute of Medical Sciences — Lucknow, Uttar Pradesh
- Post Graduate Institute of Medical Education and Research (PGIMER) — Chandigarh, Chandigarh
- Centre for DNA Fingerprinting & Diagnostics with Nizam’s Institute of Medical Sciences — Hyderabad, Telangana
- King Edward Memorial Hospital — Mumbai, Maharashtra
- Institute of Post-Graduate Medical Education and Research (IPGMER) — Kolkata, West Bengal
- Centre for Human Genetics with Indira Gandhi Hospital — Bengaluru, Karnataka
- Institute of Child Health and Hospital for Children (ICH & HC) — Chennai, Tamil Nadu
- All India Institute of Medical Sciences (AIIMS) — Jodhpur, Rajasthan
- Sree Avittam Thirunal Hospital (SAT), Government Medical College — Thiruvananthapuram, Kerala
- All India Institute of Medical Sciences (AIIMS) — Bhopal, Madhya Pradesh
- Regional Institute of Medical Sciences (RIMS) — Imphal, Manipur
- All India Institute of Medical Sciences (AIIMS) — Patna, Bihar
- Assam Medical College & Hospital — Dibrugarh, Assam
Voluntary contributions / crowdfunding (separate from CoE funding): https://rarediseases.mohfw.gov.in/
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.
("Methylmalonic aciduria due to transcobalamin receptor defect" OR "Methylmalonic acidemia, TCb1R type" OR "Methylmalonic acidemia, TCbIR type" OR "CD320 methylmalonic acidemia" OR "methylmalonic acidemia caused by mutation in CD320") OR ("CD320" OR "CD320 syndrome" OR "CD320-related")ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Methylmalonic aciduria due to transcobalamin receptor defect" OR "Methylmalonic acidemia, TCb1R type" OR "Methylmalonic acidemia, TCbIR type" OR "CD320 methylmalonic acidemia" OR "methylmalonic acidemia caused by mutation in CD320"
Study-type breakdown: 0 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 (9562) is implausibly high for prevalence class "<1 / 1 000 000" — treat as possible over-matching, not a measure of research intensity
Ingested 2026-07-27T11:50:16.113Z