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Start free with EleplanFibrous dysplasia of bone
ORPHA:249Malformation syndrome
What it is
A rare, benign, primary bone dysplasia characterized by progressive replacement of normal bone and marrow with fibrous connective tissue in either one (monostotic) or multiple (polyostotic) bones. Clinical manifestations depend on the anatomic location of the replacement and may include bone pain, deformities, pathological fractures, and cranial nerve deficits.
Key facts
- Age of onset
- Adolescent, Adult, Childhood
- Inheritance
- Not applicable
- Classified as
- Malformation syndrome
Signs and symptoms
Very common80–99%
5Common30–79%
15- Abnormality of facial skeleton
- Abnormality of femur morphology
- Abnormality of the mandible
- Abnormality of the maxilla
- Abnormal zygomatic bone morphology
- Antalgic gait
- Bone pain
- Bowing of the long bones
- Cortical irregularity
- Elevated circulating alkaline phosphatase concentration
- Hypophosphatemia
- Patchy reduction of bone mineral density
- Pathologic fracture
- Rickets
- Thin bony cortex
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.
Genes reported in subtypes
Orphanet records this gene on 2 more specific entries under this disorder, not on this entry itself:
A well-studied disease is usually split into subtypes, and the gene is curated on whichever one the evidence belongs to. Open a subtype to see which gene goes with it.
ICD-10 codes
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.
Related health topics
Reached through the ICD-10 categories this disease is filed under, so these describe the broader group rather than this disease specifically.
Cross-references
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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