Rare diseases · Sign or symptom
Elevated hemoglobin A1c
HP:0040217
What it means
An increased concentration of hemoglobin A1c (HbA1c), which is the product of nonenzymatic attachment of a hexose molecule to the N-terminal amino acid of the hemoglobin molecule. This reaction is dependent on blood glucose concentration, and therefore reflects the mean glucose concentration over the previous 8 to 12 weeks. The HbA1c level provides a better indication of long-term glycemic control than one-time blood or urinary glucose measurements.
Rare diseases that can present with this2
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, and Orphanet separately records 1 disease where this sign is specifically absent. A sign on this page is a conversation to have with a clinician, not a conclusion.
Part of the broader category
Also called: Elevated glycated haemoglobin · Elevated glycated hemoglobin · Elevated glycosylated haemoglobin · Elevated glycosylated hemoglobin · Elevated haemoglobin A1c · Elevated HbA1c · Increased HbA1c levels
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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.