Jansen's metaphyseal chondrodysplasia: a disorder due to a PTH/PTHrP receptor gene mutation.
Jansen's metaphyseal chondrodysplasia (JMC) is a rare genetic disorder that is characterized by short-limbed dwarfism and severe, agonist-independent hypercalcemia. An activating PTH/PTHrP receptor mutation that results in constitutive cAMP accumulation was recently identified in the genomic DNA of a patient with this disorder. These findings provide a plausible explanation for the abnormal regulation of growth-plate chondrocytes and mineral ion homeostasis in JMC, and may have significant implications for understanding the broader biological role of PTHrP and its receptor.
Jüppner
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Endocrine Unit, Department of Medicine and Children's Service, Massachusetts General Hospital and Harvard Medical School, Boston, MA 02114, USA.