Rare diseases · Sign or symptom

Wormian bones

Extra bones within cranial sutures

HP:0002645

What it means

The presence of extra bones within a cranial suture. Wormian bones are irregular isolated bones which appear in addition to the usual centers of ossification of the cranium.

Irregular, isolated bones in the lambdoidal suture or at the fontanelles.

Rare diseases that can present with this28

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: Intra sutural bones · Intrasutural bones · Islands of bone within cranial sutures

Wormian bones

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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.