Rare diseases · Sign or symptom
Diaphyseal undertubulation
Thickening of shaft or central part of long bones
HP:0005019
What it means
Tubulation refers to the size and shape of tubular bones. In children and adolescents, the modeling process regulates normal bone growth. Final shaft (tube) diameter depends on appositional bone growth and the equilibrium between periosteal and endosteal bone resorption and formation. Undertubulation refers to a broad, widened form of the shafts (diaphyses) of long bones.
Rare diseases that can present with this13
Very common80–99%
11The 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: Diaphyseal widening · Undertubulated long bones · Undertubulation of diaphyses
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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.