What Is Fibrodysplasia Ossificans Progressiva (FOP)?

Fibrodysplasia ossificans progressiva (FOP) is a rare muskuloskeletal condition where, after birth and progressively through life, muscles and tendons are gradually transformed into bone (a process called ossification). This creates a second “skeleton” of extra bone, which makes movement impossible.

The cause of FOP is unknown. Symptoms of the genetic condition include:

    Progressive loss of mobility
  • Episodes of muscle swelling and inflammation followed by rapid ossification after trauma to a muscle
  • Difficulty speaking and eating as mouth becomes affected
  • Malformed big toes present at birth: This abnormality often helps distinguish FOP from other musculoskeletal conditions

Diagnosis of Fibrodysplasia Ossificans Progressiva (FOP)

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.

Genetic testing can determine whether you have fibrodysplasia ossificans progressiva.

Treatment at Penn

Currently, there is no cure for FOP. Courses of high-dose corticosteroids at the start of a flare-up can reduce some of the symptoms of the condition.

Share This Page: