Rare diseases · Sign or symptom

Type I diabetes mellitus

Type 1 diabetes

HP:0100651

What it means

A chronic condition in which the pancreas produces little or no insulin. Type I diabetes mellitus is manifested by the sudden onset of severe hyperglycemia with rapid progression to diabetic ketoacidosis unless treated with insulin.

The onset of type 1 diabetes is typically during adolescence, but it can develop at any age.

In everyday care

Most people with this sign do not have a rare disease — it appears in common conditions far more often. These general reference pages cover the same topic:

Rare diseases that can present with this39

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: Diabetes mellitus Type I · Insulin-dependent diabetes mellitus · Juvenile diabetes mellitus · Type I diabetes

Type I diabetes mellitus

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This 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.