Fibrodysplasia ossificans progressiva, or FOP, is a disorder wherein the skeleton’s bone builds outside of it. Abnormal bone growth replaces connective tissues like ligaments and tendons.

It’s the only known condition in which one organ system transforms into another. Also, this chronic, progressive illness has no known cure. Nevertheless, the purpose of treatment is to alleviate symptoms as much as possible.


People with bone overgrowth syndrome FOP are more likely to have short, malformed toes. People’s trunks, limbs, hips, and backs are all affected by the condition.

The following symptoms may occur as the disease progresses:

  • Deformation of the spine
  • Restricted breathing, which may result in an infection in the respiratory system
  • Hearing impairment
  • Restricted movement due to bone growth in the joints
  • Due to a lack of mobility, agility issues can arise.
  • Difficulty in eating due to limited jaw movement
  • Poor blood flow

However, fibrodysplasia ossificans progressiva does not lead to additional growth of the bone in the following body parts:

  • diaphragm
  • cardiac muscle
  • tongue
  • extraocular muscles
  • smooth muscle


Because it’s so unusual, most physicians have never seen an FOP case. Nevertheless, diagnosis is based on medical and clinical history. Symptoms, such as the following, will help your doctor diagnose your condition:

  • spontaneous flare-ups of inflammation or soft tissue swelling
  • increased flare-ups after injury, viral disease, or immunizations
  • difficulty moving
  • frequent injury due to falling
  • malformations of the big toe

Moreover, in imagery tests, such as X-rays and MRIs, excess bone formation can be seen. Furthermore, it’s critical to acquire an accurate diagnosis as soon as possible. This is to avoid further complications since certain tests and treatments for other disorders can trigger flare-ups and promote bone growth.


There is no way to stop the sickness from progressing. Nevertheless, therapy for certain symptoms can improve living conditions. Some of the following are:

  • anti-inflammatory nonsteroidal drugs
  • corticosteroids to reduce pain and inflammation
  • helping devices for walking, like special shoes or braces
  • occupational therapy

Nothing can make the new bones go away. Moreover, surgical procedures would only lead to more growth of the bone.

What You Should Avoid When You Have FOP

  • Biopsy
  • Intramuscular injections
  • Dental work (can be done but must be performed with great caution)
  • Injuries or blunt trauma

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