Rare diseases · Sign or symptom

Tooth agenesis

Decreased tooth count

HP:0009804

What it means

The absence of one or more teeth from the normal series by a failure to develop

Teeth agenesis needs to be confirmed by X-rays. Teeth agenesis encompasses hypodontia, oligodontia, and anodontia. The total number and the type of teeth missing should be added to the description. The clinical absence of a tooth due to a disturbed eruption should not be termed teeth agenesis but a missing tooth.

Rare diseases that can present with this46

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: Decreased number of teeth · Dental agenesis · Failure of development of some teeth · Fewer teeth than normal · Missing some teeth · Reduced number of teeth · Teeth, agenesis

Tooth agenesis

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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.