Fibrodysplasia Ossificans Progressiva

Fibrodysplasia ossificans progressiva (FOP) is a disorder in which muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bone, forming bone outside the skeleton that stops movement. This process generally happens in early childhood, starting with the neck and shoulders and going down the body and into the limbs.

      Extra-skeletal bone formation causes evental loss of mobility as the joints become affected. Inability to fully open the mouth may cause difficulty in talking and eating. Over time, people with this disorder may experience malnutrition due to eating problems. They may also have breathing difficulties as a result of extra bone forming around the rib cage that restricts inhaling and exhaling.

       Fibrodysplasia ossificans progressiva is a very rare disorder, believed to occur in approximately 1 in 2 million people worldwide. Several hundred cases have been reported.

        People with FOP are generally born with malformed big toes. This abnormality of the big toes is a characteristic feature that helps to distinguish this disorder from other bone and muscle problems. 

In 1692, French physician Guy Patin met with a patient who had FOP and mentioned the encounter in his writings. In 1736, British physician John Freke described at length an adolescent whose diagnosis included swellings throughout his back.It is estimated that FOP affects about 3,500 people worldwide, or approximately one in two million people. Such statistics may be better grasped by the following example: if a large football stadium holds 100,000 fans, one would need to fill nearly 20 football stadiums to find one person who has FOP. At the present time, researchers are aware of approximately 800 people throughout the world who have FOP.