Stone Man Syndrome

According to Ancient Greek mythology, there once lived a woman cursed with ravenous serpents for hair and the ability to turn all those who gaze into her eyes to stone. Her name was Medusa and she was a menacing foe, defeating her enemies by permanently petrifying them. Medusa’s tale is one from thousands of years ago, but one condition affecting people today seems to come quite close. Fibrodysplasia ossificans progressiva, also known as FOP or “Stone Man Syndrome,” is an unusually rare condition that greatly affects the patient and complicates their life. 

The name itself is complex, but can be simplified and deciphered. The root “fibro-” means fibers or fibrous, while “dysplasia” means an abnormal growth of tissue or organs. Therefore, “fibrodysplasia” equates to the abnormal growth of fibrous tissue or organs. To continue, “ossificans” is defined as the growth of bone within a muscle or soft tissue after injury, and “progressiva” is progressive. Knowing that bone is fibrous connective tissue (it contains many collagen fibers) and putting together the basic etymology of all these words and roots, FOP is a disease in which extra-skeletal bone growth occurs, eventually replacing muscles and soft tissues with bone - or as Medusa would say, turning them into “stone.”

So, what exactly is the relevance of this condition? While rare and affecting about 1 in 1.6 million people, the characteristics of the disease are fascinating and learning about uncommon conditions can only expand one's horizons. FOP is known to be caused by a harmful mutation in an activin receptor gene. This gene contains instructions regarding how to produce a certain member of the bone morphogenetic protein type 1 receptors. To boil that down, these proteins aid in the formation of bone and cartilage. The mutation of solely one gene out of 6 billion base pairs in the human genome brings upon the painful condition, justifying its rarity. The mutated receptor is then observed to change shape, eventually losing control over its own activity and regulation. Extraordinarily, FOP is more often caused by a new mutation (occurring in a person whose ancestry never suffered from it). This makes family history a minimal or completely null variable in the process of analyzing why a patient has the condition, and it means that the mutation has actually been acquired rather than hereditarily passed on from parent to offspring.

When the body experiences trauma from a fall, viral illness, or even surgery, "flare-ups" occur, in which the mutated receptor is constantly active. The constant state of activity is what causes the progressive growth of bone and cartilage. This symptom is known as heterotypic ossification, or HO, and can be observed with an x-ray. In greater detail, progressive HO is continuous abnormal bone growth in areas where bone does not usually grow. These areas could include tendons, muscles, etc. This new bone is estimated to grow at 3 times the rate of regular bone growth, and patients describe living with it as having choppy, painful joints.

While bone growth occurs rapidly when triggered, a person with FOP will not turn completely to bone in a matter of seconds. It occurs in short flare-ups throughout their lives. This bone formation is sporadic based on trauma, but its disability is cumulative, meaning that the effects from the flare-ups add up, affecting an individual increasingly as time progresses. Muscles and tissues are independent from bone for a reason; they have several differing functions. The attempts to perform those functions with extra-skeletal bone isn't possible. 

Currently, there are no treatments for FOP. Since surgery causes further trauma, the medical field is unable to take action in removing the bone surgically. However, painful soft tissue swelling after the trauma mentioned previously is often misdiagnosed as tumors - when operated on, this will only further the condition. Truly a heartbreaking condition for individuals and their families, research is being conducted to find a solution, but there is far to go before we truly understand how to tackle the Stone Man Syndrome. 

Fibrodysplasia ossificans progressiva. (n.d.). Retrieved July 16, 2019, from https://rarediseases.info.nih.gov/diseases/6445/fibrodysplasia-ossificans-progressiva
Fibrodysplasia ossificans progressiva - Genetics Home Reference - NIH. (2019, July 16). Retrieved from https://ghr.nlm.nih.gov/condition/fibrodysplasia-ossificans-progressiva#diagnosis
FOP Symptoms. (n.d.). Retrieved July 10, 2019, from https://www.ifopa.org/symptoms
Fujii, M., Takeda, K., Imamura, T., Aoki, H., Sampath, T. K., Enomoto, S., . . . Miyazono, K. (1999, November). Roles of bone morphogenetic protein type I receptors and Smad proteins in osteoblast and chondroblast differentiation. Retrieved July 16, 2019, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC25680/
Kaplan, F. S., Le Merrer, M., Glaser, D. L., Pignolo, R. J., Goldsby, R. E., Kitterman, J. A., . . . Shore, E. M. (2008, March). Fibrodysplasia ossificans progressiva. Retrieved July 16, 2019, from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2424023/
Lauriello, S. (2019, May 29). This 23-Year-Old Lives With a Debilitating Condition That's Slowly Turning Her Muscle Into 'Stone'. Retrieved July 10, 2019, from https://www.health.com/mind-body/fibrodysplasia-ossificans-progressiva

Image Credit: Unknown. Stone Man Syndrome, 1 Jan. 1970, www.punnettssquare.com/2015/09/stone-man-syndrome.html. Retrieved June 26, 2020.

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