ORPHA:859
Transcobalamin II deficiency
Also known as: Inherited deficiency of transcobalamin II
Query health: suspect — Only one of 2 strategies returned hits (phrase).
Publications
321
74.1th percentile
Trials
0
Interventional, condition-specific
Researchers
1,426
Distinct authors in sample
Gene link
TCN2
Definitive
Readiness
2/6
Stages with a signal
Clinical definition (Orphanet)
Transcobalamin deficiency (TC) is a disorder of cobalamin transport that usually presents during the first few months of life and is characterized by megaloblastic anemia, , vomiting, weakness and pancytopenia.
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:0010149
- OMIM:275350
- UMLS:C0342701
- NCIT:C142806
Additional Mondo synonyms (3)
TCN2 deficiency · inherited deficiency of transcobalamin · transcobalamin II deficiency
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.”
2/6 stages with a signal
No matched interventional trial; the gene is known and literature exists — preclinical or natural-history work may still be the practical next step.
- Gene identifiedPresent
Definitive — TCN2
- LiteraturePresent
321 matched papers (151 in last 10 years) Source
- Phenotype characterisedNot checked
Not yet enriched from Monarch / HPO
- Animal modelNot checked
Not yet enriched from Monarch / Alliance
- Orphan designationNot checked
FDA/EMA orphan-drug designation not enriched yet
- 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 (TCN2).
GenCC classification: Definitive.
Phenotypes (Monarch / HPO)
Not enriched in this build — Monarch phenotype joins were not run for this record.
Animal models (Monarch / Alliance)
Not enriched in this build.
Literature
Is anyone studying this?
321
321 papers have ever been published on this condition (under this name). For scale, breast cancer has over 700,000. Median papers in the last 10 years for a rare disease in this dataset (publications denominator n=5449) is 41.
321 papers since the earliest indexed year in this search — median last-10-year count for a rare disease in this dataset is 41 (publications denominator n=5449).
151 in the last 10 years · medium confidence · 74.1th percentile (publications denominator)
Phrase hits: 321 · MeSH hits: 0
Who's working on it?
1,426
Distinct author names in 200 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.
- 01Chiang CP10 papers · 2025
Department of Dentistry, Far Eastern Memorial Hospital, Taipei, Taiwan.
Papers in Europe PMC - 02Wu YH10 papers · 2025
Department of Dentistry, Far Eastern Memorial Hospital, Taipei, Taiwan.
Papers in Europe PMC - 03Sun A9 papers · 2025
Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.
Papers in Europe PMC - 04Yu-Fong Chang J7 papers · 2025
Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.
Papers in Europe PMC - 05Lee YP6 papers · 2025
Department of Dentistry, Hualien Tzu Chi Hospital, Buddhist Tzu Chi Medical Foundation, Hualien, Taiwan.
Papers in Europe PMC - 06Wang YP6 papers · 2025
Graduate Institute of Clinical Dentistry, School of Dentistry, National Taiwan University, Taipei, Taiwan.
Papers in Europe PMC - 07Hall CA3 papers · 1992
Stratton Veterans Affairs Medical Center, Albany, New York 12208.
Papers in Europe PMC - 08Jin YT3 papers · 2022
Department of Pathology, Taiwan Adventist Hospital, Taipei, Taiwan.
Papers in Europe PMC - 09
- 10Sweetman L3 papers · 2006Papers in Europe PMC
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. 1 observational study did — shown below because natural-history and cohort work can be an important step toward a trial.
Data as of 27 July 2026
No matched interventional trials. This is true for 73% of diseases in the trials denominator (5114 of 7003). Here are the researchers publishing on it.
medium confidence · 36.5th 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.
Observational and natural-history studies
1 observational study matches this condition. These do not test a treatment and are not counted in the interventional-trial headline, but they are genuine research: natural-history work often defines the endpoints needed for a future rare-disease trial, and families may be able to enroll.
None of the matched observational studies is currently listed as recruiting.
Where to find support
We do not yet link condition-specific patient organisations. These umbrella groups support undiagnosed and ultra-rare families:
India — NPRD
Last verified 2026-07-26This 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.
"Transcobalamin II deficiency" OR "Inherited deficiency of transcobalamin II" OR "Inherited deficiency of the transcobalamin II" OR "TCN2 deficiency" OR "inherited deficiency of transcobalamin" OR "inherited deficiency of the transcobalamin"
ClinicalTrials.gov query (quoted phrases + MeSH via query.cond, plus recall-expansion terms when used):
"Transcobalamin II deficiency" OR "Inherited deficiency of transcobalamin II" OR "Inherited deficiency of the transcobalamin II" OR "TCN2 deficiency" OR "inherited deficiency of transcobalamin" OR "inherited deficiency of the transcobalamin" OR "TCN2"
Recall-expansion terms: TCN2
Study-type breakdown: 0 interventional · 1 observational · 0 expanded access. Only interventional studies enter the trial headline.
Query health: suspect — strategies attempted: phrase, recall-expansion; 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 (321) is high for prevalence class "<1 / 1 000 000" — confidence capped at medium
Ingested 2026-07-26T15:40:33.264Z