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Jansen-type metaphyseal chondrodysplasia
Epidemiology: rare
Pathology:
- lack of parathyroid gland abnormalities
Genetics:
- point mutation in parathyroid hormone receptor gene has been identified in one patient [1]; His -> Arg point mutation results in constitutive elevations of cAMP, but not inositol phosphate in COS-7 cells expressing the mutation
Clinical manifestations:
- short stature, short-limbed dwarfism
- brachycephaly
- micrognathia
- deafness
- hypertelorism
- nephrocalcinosis
- osteopenia
- pathologic fractures
- asymptomatic, but often profound hypercalcemia & hypophosphatemia
Laboratory:
- serum calcium: often profound hypercalcemia
- serum phospate: hypophosphatemia
- serum PTH & PTH-related peptide levels are low to normal
General
dwarfism (nanism)
genetic disease of bone/skeletal system
osteochondrodysplasia
Database Correlations
OMIM correlations
MORBIDMAP 168468
References
- Schipani E et al
A constitutively active mutant PTH-PTHrP receptor in
Jansen-type metaphyseal chondrodysplasia.
Science. 1995 Apr 7;268(5207):98-100.
PMID: 7701349
- OMIM 156400