Skip to content

IEMbase 0193: EBP-related chondrodysplasia punctata 2

Scope

Field Value
IEMbase ID 193
Nosology 14.7.1.01
Gene EBP
External IDs OMIM:302960; ORPHA:79255
Generated mapping UNMAPPED; best candidate Rhizomelic_Chondrodysplasia_Punctata_Type_1.yaml
Candidate DisMech targets None valid; chondrodysplasia punctata candidates are not EBP/CDPX2
Review date 2026-07-07

IEMbase phenotype signal

IEMbase represents this as EBP-related chondrodysplasia punctata 2, with alternate labels Conradi-Hunermann syndrome, 3beta-hydroxysteroid-delta8,delta7-isomerase deficiency, and CDPX2. Treatability is marked unknown.

The biochemical rows include increased plasma 8(9)-cholestenol and 8-dehydrocholesterol. Characteristic clinical rows include alopecia, dystrophic nails, follicular atrophoderma, punctate calcifications of epiphyses, punctate calcifications of the larynx and trachea, and rhizomelia. Additional rows include cataract, cervical compressive myelopathy, neonatal ichthyosiform erythroderma, micrognathia, microphthalmia, midface hypoplasia, polydactyly, renal anomalies or hypoplasia, scoliosis, and vertebral anomalies. No treatment rows are listed.

DisMech phenotype coverage

No valid local EBP/CDPX2 target was found. The generated best candidate, Rhizomelic_Chondrodysplasia_Punctata_Type_1.yaml, is a PEX7/peroxisomal plasmalogen disorder rather than an EBP sterol-isomerase disorder. Chondrodysplasia_Punctata_Tibial-metacarpal_Type.yaml is also a different chondrodysplasia punctata entity with unresolved molecular cause and should not be used for EBP-related CDPX2.

Concordance and completeness

Judgement: true local disease gap; generated chondrodysplasia punctata candidate is false.

IEMbase gives a specific sterol-biosynthesis profile for EBP/CDPX2: 8(9)-cholestenol and 8-dehydrocholesterol accumulation with skin, hair, nail, punctate-calcification, skeletal, ocular, renal, and spine involvement. Local DisMech has related chondrodysplasia punctata records, but their genes and mechanisms are distinct.

Curation actions

  • Do not map this record to PEX7-related RCDP1 or tibial-metacarpal chondrodysplasia punctata.
  • Add a future EBP/CDPX2/Conradi-Hunermann syndrome target if sterol biosynthesis skeletal dysplasias are in scope.
  • Seed that entry with 8(9)-cholestenol/8-dehydrocholesterol, alopecia, follicular atrophoderma, ichthyosiform erythroderma, punctate epiphyseal and airway calcifications, rhizomelia, cataract, and vertebral/renal anomalies.