Jansen's metaphyseal chondrodysplasia

Jansen's Metaphyseal Chondrodysplasia or JMC is a disease of the parathyroid hormone receptors.

It is extremely rare and as of 2007 there are only 17 reported cases world-wide.

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Presentation

It causes short stature, with normal epiphyseal plates but disorganized metaphyseal regions. Hypercalcemia (Elevated levels of calcium in the blood) is often associated with Jansen's, but is not necessarily indicative of JMC.

Physical irregularities often associated with Jansen's include: prominent or protruding eyes, a high arched palate, micrognathia or abnormal smallness of the jaws - particularly the lower (mandible) jaw, choanal stenosis, wide cranial sutures and irregular formation of the long bones which can resemble rickets.

Synonyms

• Murk Jansen Type Metaphyseal Chondrodysplasia
• Jansen Metaphyseal Dysostosis
• Jansen Disease
• JMC

Eponym

It is named for Murk Jansen.^[1][2]

Related Links

• Metaphyseal chondrodysplasia, Jansen type -- OrphaNet Information

• OrphaNet Home

• 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)

Resources

• Little People of America, Inc.
• Human Growth Foundation
• MAGIC Foundation for Children's Growth
• NIH/National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
• Craniofacial Foundation of America

References