Rare diseases · Sign or symptom
Abnormal vitamin B12 concentration
HP:0004341
What it means
The concentration of vitamin B12 (or one of its metabolites) in the blood circulation is outside the limits of normal.
Rare diseases that can present with this4
The range is how often this sign appears among people diagnosed with each disease — it is not a probability of having any of them. Many of these signs also occur in common, non-rare conditions. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Abnormal serum cobalamin level · Abnormal vitamin B12 level · Abnormality of the vitamin B12 metabolism
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Start free with EleplanThis page uses the Human Phenotype Ontology (2026-06-23) — Human Phenotype Ontology Consortium, hpo.jax.org. Disease associations from Orphanet (INSERM), CC BY 4.0. Content is educational and is not medical advice.