NOTICE: This health information was not created by the University of Michigan Health System (UMHS) and may not necessarily reflect specific UMHS practices. For medical advice relating to your personal condition, please consult your doctor. Complete disclaimer


National Organization for Rare Disorders, Inc.

It is possible that the main title of the report Pseudoachondroplasia 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.


  • spondyloepiphyseal dysplasia, type pseudoachondroplasia

Disorder Subdivisions

  • None

General Discussion

Pseudoachondroplasia (PSACH) is a short-limbed dwarfing condition characterized by disproportionate short stature, joint laxity, attractive face and early onset osteoarthritis. Joint laxity is marked in the fingers, wrists and elbows and knees. Joint pain is common at all ages with osteoarthritis occurring at an early age and affecting all the joints. Abnormal curvature of the spine (scoliosis) is an occasional complication. Intelligence is normal. Pseudoachondroplasia is caused by a mutation in the cartilage oligomeric matrix protein or COMP gene and is transmitted in an autosomal dominant pattern. Thirty percent of cases are familial with an affected parent transmitting the condition, while 70% occur as a random, new (de novo) mutation in COMP with no previous family history.

Pseudoachondroplasia was first described in 1959 by Drs. Maroteaux and Lamy and was originally believed to be a type of spondyloepiphyseal dysplasia. Also, although previously considered to be composed of at least four different forms, differentiated by severity and inheritance pattern, it has now considered a single, distinct disorder caused by mutations in the COMP gene.


Human Growth Foundation
997 Glen Cove Avenue
Suite 5
Glen Head, NY 11545
Tel: (516)671-4041
Fax: (516)671-4055
Tel: (800)451-6434

MAGIC Foundation
6645 W. North Avenue
Oak Park, IL 60302
Tel: (708)383-0808
Fax: (708)383-0899
Tel: (800)362-4423

March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763

Little People of America, Inc.
250 El Camino Real Suite 201
Tustin, CA 92780
Tel: (714)368-3689
Fax: (714)368-3367
Tel: (888)572-2001

Restricted Growth Association
PO Box 5137
Yeovil, BA20 9FF
United Kingdom
Tel: 03001111970
Fax: 03001112454

NIH/National Institute of Arthritis and Musculoskeletal and Skin Diseases
Information Clearinghouse
One AMS Circle
Bethesda, MD 20892-3675
Tel: (301)495-4484
Fax: (301)718-6366
Tel: (877)226-4267
TDD: (301)565-2966

Coalition for Heritable Disorders of Connective Tissue (CHDCT)
4301 Connecticut Avenue, NW Suite 404
Washington, DC 20008
Tel: (202)362-9599
Fax: (202)966-8553
Tel: (800)778-7171

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

European Skeletal Dysplasia Network
Institute of Genetic Medicine
Newcastle University
International Centre for Life
Central Parkway
Newcastle upon Tyne, NE1 3BZ
United Kingdom
Tel: 441612755642
Fax: 441612755082

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated:  11/20/2014
Copyright  2002, 2003, 2014 National Organization for Rare Disorders, Inc.

This information does not replace the advice of a doctor. Healthwise, Incorporated disclaims any warranty or liability for your use of this information. Your use of this information means that you agree to the Terms of Use. How this information was developed to help you make better health decisions.

Healthwise, Healthwise for every health decision, and the Healthwise logo are trademarks of Healthwise, Incorporated.