Important
It is possible that the main title of the report Jansen Type Metaphyseal Chondrodysplasia is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.

Synonyms

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

Disorder Subdivisions

• None

General Discussion

Jansen type metaphyseal chondrodysplasia is an extremely rare progressive disorder in which portions of the bones of the arms and legs develop abnormally with unusual cartilage formations and subsequent abnormal bone formation at the large (bulbous) end portions (metaphyses) of these long bones (metaphyseal chondrodysplasia). As a result, affected individuals exhibit unusually short arms and legs and short stature (short-limbed dwarfism), findings that typically become apparent during early childhood. Abnormal cartilage and bone development may also affect other bones of the body, particularly those of the hands and feet (i.e., metacarpals and metatarsals). Infants with Jansen type metaphyseal chondrodysplasia may also have characteristic facial abnormalities and additional skeletal malformations. During childhood, affected individuals may begin to exhibit progressive stiffening and swelling of many joints and/or an unusual "waddling gait" and squatting stance. In addition, affected adults may eventually develop abnormally hardened (sclerotic) bones especially in the back of the head (cranial bones), which, in some cases, may lead to blindness and/or deafness. In addition, in some cases, affected individuals have abnormally high levels of calcium in the blood (hypercalcemia). The range and severity of symptoms may vary from case to case. Most cases of Jansen type metaphyseal chondrodysplasia occur randomly as the result of a spontaneous genetic change (i.e., new genetic mutation)

Resources

Human Growth Foundation
997 Glen Cove Avenue
Glen Head, NY 11545
Tel: (516)671-4041
Fax: (516)671-4055
Tel: (800)451-6434
Email: hgf1@hgfound.org
Internet: http://www.hgfound.org/

MAGIC Foundation for Children's Growth
6645 W. North Avenue
Oak Park, IL 60302
Tel: (708)383-0808
Fax: (708)383-0899
Tel: (800)362-4423
Email: mary@magicfoundation.org
Internet: http://www.magicfoundation.org

Little People of America, Inc.
250 El Camino Real
Suite 201
Tustin, CA 92780
Tel: (714)368-3689
Tel: (888)572-2001
Email: info@lpaonline.org
Internet: http://www.lpaonline.org

National Craniofacial Foundation
3100 Carlisle Street
Suite 215
Dallas, TX 75204
Tel: (800)535-3643

NIH/National Arthritis and Musculoskeletal and Skin Diseases Information Clearinghouse
1 AMS Circle
Bethesda, MD 20892-3675
USA
Tel: 3014954484
Fax: 3017186366
Tel: 8772264267
TDD: 3015652966
Email: NIAMSinfo@mail.nih.gov
Internet: http://www.niams.nih.gov/Health_Info

NIH/Nat'l Institute on Deafness & Other Communication Disorders Information Clearinghouse
1 Communication Ave
Bethesda, MD 20892-3456
Tel: (301)402-0900
Fax: (301)907-8830
Tel: (800)241-1044
TDD: (800)241-1105
Email: nidcdinfo@nidcd.nih.gov
Internet: http://www.nidcd.nih.gov

Craniofacial Foundation of America
975 East Third Street
Chattanooga, TN 37403
Tel: (423)778-9192
Fax: (423)778-8172
Tel: (800)418-3223
Email: farmertm@erlanger.org
Internet: http://www.craniofacialcenter.com