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  • Jaejeong & Jaeah Kim

Fibrodysplasia ossificans progressiva: Turning to Stone

(Advanced Bony Manifestations of FOP in a 39-year-old Man)

We recently posted a bone dissection video (which you can check out here) where we discussed the anatomy and functions of one of the most important organs in the human body. Although the skeletal system may not be as structurally complex as many other organ systems in our bodies such as the nervous or cardiovascular systems, there are still a lot of places where something could go wrong– Bone infections, osteoarthritis, osteoporosis, Paget’s disease, rheumatoid arthritis, and scoliosis, are just a few of the thousands of bone diseases recorded. However, none of these even come close to Fibrodysplasia ossificans progressiva, one of the most serious bone conditions known.

Fibrodysplasia ossificans progressiva is a very rare disease –occurring in approximately 1 in 2 million people worldwide– where the muscle/connective tissues such as tendons and ligaments are gradually ossified (meaning turning into bone). What this means, is that for people with fibrodysplasia ossificans progressiva, extra-skeletal bone develops outside of the skeleton. This ossification process usually becomes noticeable during childhood, starting at the shoulders and neck, then slowly progressing down towards the rest of the body and the limbs.

As you can probably tell, fibrodysplasia ossificans progressiva causes massive complications to those living with the disease. First of all, extra-skeletal bone development greatly constricts movement (because the connective/muscle tissues of the joint ossify), and people with fibrodysplasia ossificans progressiva often experience malnutrition & speech issues, due to the fact that their mouths are unable to fully open. In addition to that, people with fibrodysplasia ossificans progressiva often have breathing difficulties due to extra bone-formation around the rib cage that restricts lung expansion. It is also important for people with fibrodysplasia ossificans progressiva to avoid any falls or invasive medical procedures, as these may trigger rapid ossification in the site of injury.

Fibrodysplasia ossificans progressiva is a genetic disorder, and is caused by mutations in the ACVR1 gene. The ACVR1 gene codes for a bone morphogenic protein (BMP), a protein which helps regulate ossification processes in the body. Therefore a mutation in the ACVR1 gene disrupts the ossification mechanism of the body, causing uncontrolled overgrowth of bones and cartilage. Firodysplasia ossificans progressive is inherited in a autosomal dominant pattern, but most new cases of it are caused by new mutations, rather than inherited genetic causes.

If you want to learn more about Fibrodysplasia ossificans progressiva, or find out ways you can help those living with this disorder, check out International Fibrodysplasia Ossificans Progressiva Association (IFOPA)’s website here.


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