Jansen's metaphyseal chondrodysplasia: Difference between revisions
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==Presentation== | ==Presentation== | ||
Jansen's metaphyseal chondrodysplasia is characterized by severe short stature, short bowed limbs, clinodactyly, prominent | Jansen's metaphyseal chondrodysplasia is characterized by severe short stature, short bowed limbs, clinodactyly, prominent cheeks, and small mandible. Other dysmorphic features associated with JMC include: prominent or protruding eyes, hypertelorism, high skull vault, high arched palate, [[micrognathia]] or abnormal smallness of the jaws - particularly the lower (mandible) jaw, [[choana|choanal]] [[atresia]], wide [[cranial sutures]] and irregular formation of the long bones which can resemble [[rickets]]. [[Nephrocalcinosis]] is also commonly seen. | ||
==Laboratory Findings== | |||
Hypercalcemia and hypophosphatemia occur despite undetectable serum levels of [[parathryoid hormone|parathryoid hormone (PTH)]]. Examination of the bone reveals normal [[epiphyseal plate]]s but disorganized [[metaphyseal]] regions. Elevated urinary calcium and phosphorus are generally found in JMC. The absence of hypercalcemia does not eliminate the disease from consideration. | |||
==Treatment== | ==Treatment== | ||
Revision as of 18:24, 10 August 2013
Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]
Synonyms and keywords: JMC; Jansen disease; Jansen metaphyseal dysostosis; Jansen type of metaphyseal chondrodysplasia; Murk Jansen type metaphyseal chondrodysplasia
Overview
Jansen's metaphyseal chondrodysplasia (JMC) is a rare disease that results from ligand-independent activating mutation of the type 1 of the parathyroid hormone receptor (PTHR1).
Historical Perspective
It is named for Murk Jansen.[1][2]
Pathophysiology
Jansen's metaphyseal chondrodysplasia is caused by constitutively active mutations in the parathyroid hormone-1 receptor on chromosome 3p21.
Presentation
Jansen's metaphyseal chondrodysplasia is characterized by severe short stature, short bowed limbs, clinodactyly, prominent cheeks, and small mandible. Other dysmorphic features associated with JMC include: prominent or protruding eyes, hypertelorism, high skull vault, high arched palate, micrognathia or abnormal smallness of the jaws - particularly the lower (mandible) jaw, choanal atresia, wide cranial sutures and irregular formation of the long bones which can resemble rickets. Nephrocalcinosis is also commonly seen.
Laboratory Findings
Hypercalcemia and hypophosphatemia occur despite undetectable serum levels of parathryoid hormone (PTH). Examination of the bone reveals normal epiphyseal plates but disorganized metaphyseal regions. Elevated urinary calcium and phosphorus are generally found in JMC. The absence of hypercalcemia does not eliminate the disease from consideration.
Treatment
There is no known treatment at present, although some investigators have tried to lessen the hypercalcemia with various forms of bisphosphonates.
References
- ↑ Jansen, M. Ueber atypische Chondrodystrophie (Achondroplasie) und ueber eine noch nicht beschriebene angeborene Wachstumsstoerung des Knochensystems: Metaphysaere Dysostosis. Z. Orthop. Chir. 61: 253-286, 1934.
- ↑ Silverthorn KG, Houston CS, Duncan BP (1987). "Murk Jansen's metaphyseal chondrodysplasia with long-term followup". Pediatric radiology. 17 (2): 119–123. doi:10.1007/BF02388087. PMID 3562109.
External links
- Metaphyseal chondrodysplasia, Jansen type -- OrphaNet Information (PDF)
- Jansen’s Metaphyseal Chondrodysplasia, Case Report, Indian Pediatrics
- Jansen Type Metaphyseal Chondrodysplasia -- National Organization for Rare Disorders (NORD)
- A Novel Parathyroid Hormone (PTH)/PTH-Related Peptide Receptor Mutation in Jansen’s Metaphyseal Chondrodysplasia, The Journal of Clinical Endocrinology & Metabolism (1)
- A Form of Jansen’s Metaphyseal Chondrodysplasia with Limited Metabolic and Skeletal Abnormalities Is Caused by a Novel Activating Parathyroid Hormone (PTH)/PTH-Related Peptide Receptor Mutation, The Journal of Clinical Endocrinology & Metabolism (2)
- Constitutively Activated Receptors for Parathyroid Hormone and Parathyroid Hormone–Related Peptide in Jansen's Metaphyseal Chondrodysplasia, The New England Journal of Medicine
- Constitutive Activation of the Cyclic Adenosine 3',5'-Monophosphate Signaling Pathway by Parathyroid Hormone (PTH)/PTH-Related Peptide Receptors Mutated at the Two Loci for Jansen’s Metaphyseal Chondrodysplasia, Molecular Endocrinology
- METAPHYSEAL CHONDRODYSPLASIA, JANSEN TYPE GenomeNet
- (Abstract Only) - Murk Jansen's metaphyseal chondrodysplasia with long-term followup (Pediatric Radiology)