Component
Human inherited transcobalamin II deficiency
Inherited low/absent functional transcobalamin II phenotype; original 1971 family had no identified DNA variant.
1 recorded relationships. Experimental role, claim status and evidence remain attached to each record.
How nutrients influence it
Every nutrient with a recorded effect on this component, credited to the nutrient that acted rather than the chapter that recorded it. Open a nutrient to see the findings and the conditions they were measured under.
Other things that act on it
Enzymes, hormones, genes, and other components with a recorded effect. These are not nutrients, so they do not count toward the arrows above. Each finding names the chapter that recorded it.
How nutrients reach it in more than one step
Chains of two or more recorded steps that end here, grouped by the nutrient they start from. Each step is a separate finding, so a chain is a route a mechanism could take, not proof that it does.
Tracing routes…
What it does
Every recorded relationship this component is part of, grouped by its role. Plain wording comes first; the technical statement follows.
What it acts on
Two infant siblings with demonstrated transcobalamin II deficiency developed megaloblastic anemia and systemic B12-deficiency manifestations at three and five weeks despite normal total serum B12.
Experimental context and source evidence
- availability_state
- machinery_impairment Imported condition classification; unverified.
- cross_nutrient
- false
- experimental_model
- Two infant siblings; chromatography/electrophoresis and family binding-capacity studies
- exposure
- Inherited TCII deficiency; carrier pattern supported recessive inheritance
- limitations
- Two-case family report; DNA variants were not identified and total serum B12 did not measure intracellular delivery.
- nutrient_topic
- Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. · Vitamin B12 (cobalamins)
- organism
- Homo sapiens
- plain_language
- Normal total B12 did not exclude a serious carrier deficiency.
- primary_references
- [hakami-1971-tcn2] Neonatal megaloblastic anemia due to inherited transcobalamin II deficiency in two siblings. (1971). https://pubmed.ncbi.nlm.nih.gov/5096637/ DOI: 10.1056/nejm197111182852103
- tissue_or_cell_type
- Systemic B12 delivery/hematopoiesis
- trigger_kind
- machinery_impairment Imported condition classification; unverified.
Vitamin B12: mechanisms, deficiency and nutrient interactions (2026-09-17) · lines 530–541
AI-assisted literature curation; primary study URLs and scope retained in the document and extraction. Not publisher full text. · supports · Two infant siblings; chromatography/electrophoresis and family binding-capacity studies · source_derived_draft · unverified_draft
### b12-abs-tcn2-inherited-functional-deficiency Two infant siblings with demonstrated transcobalamin II deficiency developed megaloblastic anemia and systemic B12-deficiency manifestations at three and five weeks despite normal total serum B12. Condition category: machinery_impairment nutrient_topic: Vitamin B12 research collection; topical membership is not evidence of a direct dietary effect. plain_language: Normal total B12 did not exclude a serious carrier deficiency. organism: Homo sapiens tissue_or_cell_type: Systemic B12 delivery/hematopoiesis experimental_model: Two infant siblings; chromatography/electrophoresis and family binding-capacity studies limitations: Two-case family report; DNA variants were not identified and total serum B12 did not measure intracellular delivery. exposure: Inherited TCII deficiency; carrier pattern supported recessive inheritance cross_nutrient: false [hakami-1971-tcn2] Neonatal megaloblastic anemia due to inherited transcobalamin II deficiency in two siblings. (1971). https://pubmed.ncbi.nlm.nih.gov/5096637/ DOI: 10.1056/nejm197111182852103
Complete structured claim and evidence
The events it takes part in
A mechanism often involves more than two components. These are the full events, with every participant and its role.
Situations it appears in
Low-supply and faulty-machinery situations recorded in the chapters where this component plays a part.
In the sources
Preserved passages that mention this component, quoted exactly. Open one to read it in context.
Open hypotheses
Proposed ideas that involve this component. They are labeled as hypotheses and do not change any recorded statement.
This is a research prototype built from draft material. It is not medical advice, and its statements still await verification against the original studies.