My Diagnosis: The Debilitating Curse of Fibrous Dysplasia
What Is Fibrous Dysplasia?
Fibrous dysplasia (FD) is a rare bone disorder that often only occurs in a single bone (monostotic FD; about 70% of cases), but rarer cases can affect multiple bones throughout the body (polyostotic FD; roughly 30% of cases). In place of bone marrow, fibrous, scar-like tissue forms, weakening the bone and potentially causing disfigurement and fractures.
FD was first described in 1938 by Dr. Lichtenstein and later in 1942 by Drs. Lichtenstein and Jaffe, who reported 15 cases of the disorder. It usually begins manifesting during childhood or adolescence but can go unnoticed for years, delaying diagnosis. It often isn't treated until adulthood.
Although any bone can be affected, the fibrous dysplasia mostly affects the following bones:
- Femur (Thighbone)
- Tibia (Shinbone)
- Humerus (Upper arm bone)
I have three lesions in my femur and one in my left shinbone. I consider myself quite lucky because FD in the skull, ribs, or hands can cause serious disfigurement and is a lot more painful. However, it also means that my entire left leg is essentially held up by weak bones with tumour-like growths.
What Causes Fibrous Dysplasia?
The cause of FD is not entirely known although scientists have linked it to a mutation of the GNAS1 gene that occurs after fertilisation. It is neither heritable nor contagious. Scientists do not know why the mutation occurs.
The GNAS1 gene encodes part of a protein called a G-protein. As a result of the mutation, this protein is overproduced, leading to an overproduction of cyclic adenosine monophosphate (cAMP) that regulates the function of osteoblasts (bone-forming cells). It is speculated that improper differentiation of these osteoblasts is one of the factors that causes FD.
Related disorders include:
What Are the Symptoms of Fibrous Dysplasia?
There are many varying symptoms of FD including:
- Bone pain
- Bone fractures—especially in the arms and legs
- Curvature of leg bones
- A waddling walk
The seriousness of these symptoms varies from person to person and depends on the severity of their condition. My own experience has been a fortunate one. I have only experienced mild to moderate bone pain and back pain as a result of bad posture and a slight curvature of my left femur. For many, FD can be a great source of pain and discomfort while for others, it can go undiagnosed for their entire lives.
How Rare Is It?
Studies estimate that one in every 15,000-30,000 have FD. Since many are undiagnosed, it is difficult to calculate exactly how many people are born with this disorder.
An analysis conducted by FODSL (Fibrous Dysplasia Support On-Line) in the year 2000 described which bones monostotic FD affects the most (using data from 318 members of their online website).
Results From a Study of Monostotic FD Patients
Percentage of Members
skull, mandible, facial bones
legs, hips, pelvis
These results suggest that for monostotic FD, the craniofacial and lower limb areas were the most common places for the disorder to manifest. The study did not include those with polyostotic FD as it is in multiple areas for them. There appeared to be no differences in results for participants of varying genders, ethnic backgrounds or locations.
Is There a Cure for Fibrous Dysplasia?
Although there is no cure for FD, symptoms can be treated as they arise. To prevent fractures, surgery is often recommended if the lesions grow to such a size that the bones become greatly weakened. Similarly, if the bone does fracture, surgery may be required to treat it.
Roughly 40% of patients with FD suffer from other related medical complications, such as insufficient levels of calcium, phosphorus, and vitamin D, as well as problems with the thyroid, kidney, liver, and skin. Most of these can be treated with a regular intake of supplements, such as vitamin D tablets.
I have recently had blood tests to see if I have any other complications. I also participate in physiotherapy sessions to improve my walking.
Overall, my own experience with fibrous dysplasia has been fine. I'm fortunate that I don't have a severe case like so many others do. I want to raise awareness of the condition, and I hope that research will continue to solve the mysteries of why people have it and how to cure it.
Questions & Answers
© 2018 Angel Harper