Isolated humero-radio-ulnar synostosis

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Isolated humero-radio-ulnar synostosis

ORPHA:3266Morphological anomaly

Also called Isolated congenital humero-radioulnar fusion

What it is

Humero-radio-ulnar synostosis is an extremely rare, genetic, congenital joint formation defect disorder characterized by uni- or bilateral fusion of the humerus, radius and ulnar bones, leading to loss of elbow motion and, in most, functional arm incapacity. It may appear as distal humeral bifurcation with absent elbow joint and shortened arm length on imaging. Hand abnormalities, namely oligoectrosyndactyly, may be associated.

Key facts

Prevalence
<1 / 1 000 000
Age of onset
Antenatal, Neonatal
Inheritance
Unknown
Classified as
Morphological anomaly

Prevalence figures describe populations, not individuals, and are often estimates from a single study. Where the figure is an incidence or a birth prevalence, it says so.

Signs and symptoms

These ranges are how often a sign appears across everyone diagnosed, not a prediction for one person — most people have some of these and not others. Orphanet also records findings that are specifically absent in this disease; those are in the data but not listed here.

ICD-10 codes

Q74.0filed under a broader ICD-10 category — shared with 17 other rare diseases

ICD-10 has no distinct code for most rare diseases, so many are filed under the nearest available one. A shared code identifies the group, not this disease — the ORPHAcode above is what identifies it.

Cross-references

GARD 2749MONDO 0017983UMLS C5925002

Orphadata Science: Free access data from Orphanet. © INSERM 1999. Data version 2026-06-23. Available under CC BY 4.0. This is a reference, not medical advice.

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