Rare diseases · Sign or symptom
Aplasia/Hypoplasia of the ulna
Absence/underdevelopment of inner forearm bone
HP:0006495
What it means
Absence or underdevelopment of the ulna.
Rare diseases that can present with this11
Very common80–99%
3Common30–79%
7The 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: Absent-hypoplastic ulnae · Absent/small ulna · Hypoplasia or unilateral/bilateral absence of ulna · Ulnar hypoplasia/aplasia
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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.