A third condition that is often confused within FOP is fibrous dysplasia. Patients with FOP are rarely misdiagnosed as having fibrous dysplasia, but the word often appears on their diagnosis because it is a much more common condition than FOP, and it sounds very similar. Very often, patients with fibrous dysplasia will find the FOP website, and think that they have FOP. Fibrous dysplasia is a condition where primitive bone cells proliferate inside the bone, weakening its structure and causing pain and disability. Fibrous dysplasia can affect any bone in the body. 

Fibrous dysplasia is caused by an activating mutation of the same gene that actually causes Progressive osseous heteroplasia (POH). This is quite an interesting and fascinating coincidence. Patients with fibrous dysplasia often have severe problems with expansion of the bone in the skull or facial regions, areas commonly affected with condition, and rarely affected in FOP. It is very easy to distinguish between fibrous dysplasia and FOP, but the source of confusion often results from the similarity in the names.

For information on FOP and POH, please click here.