Fibrodysplasia Ossificans Progressiva

National Organization for Rare Disorders, Inc.

Skip to the navigation

It is possible that the main title of the report Fibrodysplasia Ossificans Progressiva is not the name you expected.

Disorder Subdivisions

  • None

General Discussion

Fibrodysplasia ossificans progressiva (FOP) is a very rare inherited connective tissue disorder characterized by the abnormal development of bone in areas of the body where bone is not normally present (heterotopic ossification), such as the ligaments, tendons, and skeletal muscles. Specifically, this disorder causes the body's skeletal muscles and soft connective tissues to undergo a metamorphosis, essentially a transformation into bone, progressively locking joints in place and making movement difficult or impossible. FOP is characterized by malformed big toes that are present at birth (congenital). Other skeletal malformations of the cervical spine and ribs and the abnormal development of bone at multiple soft tissue sites may lead episodically to stiffness in affected areas, limited movement, and eventual ankylosis of affected joints (neck, shoulders, elbows, hips knees, wrists, ankles, jaw, often in that order).

Episodic flare-ups (pre-osseous soft tissue swellings) of FOP usually begin during early childhood and progress throughout life. Most cases of FOP occur as the result of a sporadic new mutation. The genetic mutation that results in this disorder has been identified. FOP is caused by the mutation of a gene in the bone morphogenetic protein (BMP) pathway, which is important during the formation of the skeleton in the embryo and the repair of the skeleton following birth.

Supporting Organizations

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

International FOP Association

101 Sunnytown Rd.
Suite 208
Casselberry, FL 32707
Tel: 407-365-4194
Fax: 407-365-3213

March of Dimes

1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763
Email: or
Website: and

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

Progressive Osseous Heteroplasia Association

5327 Westpointe Plaza Drive #113
Columbus, OH 43228
Tel: (614)887-7642

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). For a full-text version of this report, 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.

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.

Last Updated:  1/29/2014
Copyright  2014 National Organization for Rare Disorders, Inc.