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Genetic and Rare Diseases Information Center (GARD)

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Fibrodysplasia ossificans progressiva

Other Names for this Disease
  • FOP
  • Myositis ossificans
  • Myositis ossificans progressiva
  • Progressive myositis ossificans
  • Progressive ossifying myositis
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Your Question

I have fibrodysplasia ossificans progressiva and recently had my first fracture.  I am currently taking medication but continue to have pain in my leg, hand, and elbow.  What are the risks of operation?  Can myositis ossificans be passed to the next generation?

Our Answer

We have identified the following information that we hope you find helpful. If you still have questions, please contact us.

What is fibrodysplasia ossificans progressiva?

Fibrodysplasia ossificans progressiva (FOP) is a disorder in which muscle and connective tissue, such as tendons and ligaments, are gradually replaced by bone (ossified). This condition leads to bone formation outside the skeleton (extra-skeletal or heterotopic bone) which constrains movement. This process generally becomes noticeable in early childhood, starting with the neck and shoulders and moving down the body and into the limbs.  People with FOP are generally born with abnormally big toes which can be helpful in clarifying the diagnosis.[1]

Trauma to the muscles of an individual with FOP, such as a fall or invasive medical procedure, or a viral illness may trigger episodes of muscle swelling and inflammation (myositis) followed by more rapid bone growth in the injured area.[1]

FOP can be caused by mutations in the ACVR1 gene and is inherited in an autosomal dominant manner.[1]
Last updated: 6/6/2011

How might fibrodysplasia ossificans progressiva be treated?

There is currently no definitive treatment.  However, a brief course of high-dose corticosteroids, such as Prednisone, started within the first 24 hours of a flare-up, may help reduce the intense inflammation and tissue swelling seen in the early stages of fibrodysplasia ossificans progressiva.  Other medications, such as muscle relaxants, mast cell inhibitors, and aminobisphosphonates, if appropriate, should be closely monitored by a physician.  Surgery to remove heterotopic and extra-skeletal bone is risky and can potentially cause painful new bone growth. [2]
Last updated: 3/21/2011

How is fibrodysplasia ossificans progressiva inherited?

Fibrodysplasia ossificans progressiva is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. [1]

Most cases of fibrodysplasia ossificans progressiva result from new mutations in the gene. These cases occur in people with no history of the disorder in their family. In only a small number of cases, an affected person has inherited the mutation from one affected parent. [1]
Last updated: 6/6/2011