IEMbase 0348: EXT2-related multiple cartilaginous exostoses type II
Scope
| Field | Value |
|---|---|
| IEMbase ID | 348 |
| Nosology | 18.2.07.01 |
| Gene | EXT2 |
| External IDs | OMIM:133701; ORPHA:52022 |
| Generated mapping | UNMAPPED; low candidate Multiple_Synostoses_Syndrome.yaml |
| Candidate DisMech targets | No exact target; Chondrosarcoma.yaml is downstream context only |
| Review date | 2026-07-07 |
IEMbase phenotype signal
IEMbase represents EXT2-CDG/multiple cartilaginous exostoses type II, an autosomal dominant disorder with prevalence listed as 1:50,000. It has no characteristic rows in the cached JSON. Clinical rows include chondrosarcoma, hypertelorism, hypotonia, intellectual disability, kyphoscoliosis, low bone mineral density, macrocephaly, and seizures. No biochemical or treatment rows are present.
DisMech phenotype coverage
The generated UNMAPPED status is correct. The low-score Multiple Synostoses Syndrome candidate is not an appropriate mapping: it covers NOG/GDF5/GDF6/FGF9 joint-fusion biology rather than EXT2 exostosin glycosyltransferase disease.
As with EXT1, local chondrosarcoma coverage can provide downstream malignancy context for EXT2-related exostoses, but it does not cover the primary multiple cartilaginous exostoses type II diagnosis.
Concordance and completeness
Judgement: true local gap; reject the Multiple Synostoses Syndrome candidate.
The disease-defining features are EXT2, autosomal dominant inheritance, multiple cartilaginous exostoses type II, and chondrosarcoma risk. The additional IEMbase neurodevelopmental and skeletal rows are useful review prompts but should be verified before import because the cached row is sparse and lacks characteristic markers.
Curation actions
- Keep this record unmapped until a dedicated EXT2-related multiple hereditary exostoses/multiple cartilaginous exostoses target exists.
- Do not map to
Multiple_Synostoses_Syndrome.yaml. - Review the IEMbase-only hypotonia, intellectual disability, macrocephaly, seizures, kyphoscoliosis, and low bone-mineral-density rows before future import.