Rare diseases · Sign or symptom
Reduced hemoglobin A
HP:0011905
What it means
Hemoglobin A (HbA) contains two globin alpha chains and two globin beta chains. HbA is normally the main adult hemoglobin, representing about 96-98 percent of all hemoglobin. This term represents a decreased in the proportion of HbA below this limit, and can be seen in various forms of thalassemia.
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: Reduced haemoglobin A · Reduced HbA
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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.