Caring for someone with this diagnosis? Eleplan keeps diagnoses, medications, documents and every specialist in one plan.
Start free with EleplanDyggve-Melchior-Clausen disease
ORPHA:239Disease
What it is
A rare, genetic primary bone dysplasia of the spondylo-epi-metaphyseal dysplasia (SEMD) group characterized by progressive short-trunked dwarfism, protruding sternum, microcephaly, intellectual disability and pathognomonic radiological findings (generalized platyspondyly with double-humped end plates, irregularly ossified femoral heads, a hypoplastic odontoid, and a lace-like appearance of iliac crests)
Key facts
- Prevalence
- <1 / 1 000 000
- Age of onset
- Infancy
- Inheritance
- Autosomal recessive
- Classified as
- Disease
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
Very common80–99%
4Common30–79%
30- Abnormality of the femoral head
- Abnormality of the hip bone
- Abnormality of the vertebral column
- Abnormality of the vertebral endplates
- Abnormal pelvis bone morphology
- Beaking of vertebral bodies
- Broad femoral neck
- Broad ribs
- Coarse facial features
- Epiphyseal dysplasia
- Gait disturbance
- Horizontal inferior border of scapula
- Hypoplasia of the capital femoral epiphysis
- Hypoplastic acetabulae
- Hypoplastic ilia
- Iliac crest serration
- Intellectual disability, severe
- Limb muscle weakness
- Metaphyseal dysplasia
- Microcephaly
- Motor delay
- Pectus carinatum
- Platyspondyly
- Rhizomelia
- Severe short stature
- Short long bone
- Short neck
- Short thorax
- Skeletal dysplasia
- Wide pubic symphysis
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.
Gene
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.
Powered by Eleplan
A rare diagnosis is just the start. Eleplan keeps the whole care plan in one place.
Diagnoses, medications, documents, appointments, and the whole care team — organized and always in sync, so you are not retelling the same story to every new specialist. With Ellie, your AI care assistant, on top of it. Free to start.