What is FOP?
Fibrodysplasia ossificans progressiva (FOP) is a disorder in which muscle tissue and connective tissue such as tendons and ligaments are gradually replaced by bone (ossified), forming bone outside the skeleton (extra-skeletal or heterotopic bone) that constrains movement. This process generally becomes noticeable in early childhood, starting with the neck and shoulders and proceeding down the body and into the limbs.
One of the rarest, most disabling genetic conditions known to medicine, FOP causes bone to form in muscles, tendons, ligaments and other connective tissues. Bridges of extra bone develop across joints, progressively restricting movement and forming a second skeleton that imprisons the body in bone. There are no other known examples in medicine of one normal organ system turning into another.
Demographics of FOP:
- Genetic disease affecting 1 in 2 million people
- No ethnic, racial, or gender patterns
- 800 confirmed cases across the globe
Clinical Characteristics of FOP:
- Malformation of the great toes is visible at birth
- Flare-ups that worsen the connection occur spontaneously or following physical trauma such as: childhood immunizations, falls, surgery, biopsy or viral illnesses
- Rogue bone growth progressively restricts movement
- Often misdiagnosed as cancer
- The exact rate of progression is unpredictable, although there appears to be a pattern to the progression (e.g., upper body in childhood and lower body in adolescence)
- No treatment exists, but a clinical trial is currently underway
FOP becomes apparent early in childhood. Infants are usually born with short, malformed big toes. Bone and joint problems make it hard for babies to learn to crawl. About half of people with FOP also have malformed thumbs.
The initial symptoms of Fibrodysplasia Ossificans Progressiva generally arise in childhood. The disease makes a progression all through the life of a sufferer. Children who are born with this disease seem to be normal from all aspects. In most cases, the only defect is an abnormality of the big toes. The toes appear to be shorter than usual and consist of a bony lump close to their base. This congenital abnormality of the toe is regarded as a defining feature of the condition that helps in its diagnosis. The progressive symptoms usually begin to arise as the child nears his or her adolescent years. Initially, painful inflammation of the soft tissues is the only symptom. These are aggravated by viral disorders or injuries. Over time, inflammations increase in number. The existent swellings turn harder due to slow transformation of the soft tissues into bone. The joints become stiffer and mobility becomes painful and difficult. Gradually, individuals with this syndrome begin losing mobility with the progression of the disease. Most sufferers require a wheelchair or other support to move about by the time they enter their thirties. The loss of mobility usually starts with the neck and shoulder region of the body and progresses downwards.
Unfortunately, there is no effective treatment for fibrodysplasia ossificans progressiva (FOP). Surgery is not an option for removing the excess bones because surgery often results in more bone formation. And these new bones don’t disappear on their own.
The good news is that researchers are investigating FOP and new treatments. For example, a drug is being developed that may help to control bone growth. Medications also are available to help relieve symptoms of FOP, such as pain and inflammation.
Since FOP is a progressive disease, it typically gets worse over time as the patient ages, but the rate of new bone formation differs for each person and the disease’s progression is generally unpredictable.
Although a person is born with FOP, extra bone may not appear at birth and he or she may go months or years without experiencing a flare-up, which signals the development of new bone.
+91 416 2282172
Department of Paediatric Orthopedics
Christian Medical College,
Ida Scudder Road,
Vellore - 632004
Tamil Nadu, India