Jansen-type metaphyseal chondrodysplasia
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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
More general terms
References
- ↑ 1.0 1.1 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: https://www.ncbi.nlm.nih.gov/pubmed/7701349
- ↑ OMIM 156400