What is POH?

Progressive Osseous Heteroplasia (POH) is often considered a ‘sister’ condition to FOP due to some similarities the two conditions share. However, they are two distinct conditions.

While FOP Friends primarily supports people and families living with FOP in the UK, we also warmly welcome and support those living with POH. POH families have found friendship, comfort, and support within the wider FOP community, reinforcing our belief that we are all stronger together.

Many medical practitioners in the UK and the US who are experts in FOP are also knowledgeable about POH. FOP Friends can help signpost you to these POH medical experts.

If you or your family are affected by POH, we warmly invite you to join our community and attend any of the events we hold.

What is POH?

Progressive Osseous Heteroplasia (POH) is an ultra-rare genetic condition in which the body forms extra bone where it should not. The exact number of people who are living with POH is unknown, but doctors estimate there are around 100 patients worldwide.

POH is caused by a mutation in the GNAS1 gene. In most cases, this mutation occurs spontaneously with no prior family history. However, when it is inherited, it is typically passed down from the father.

The process of forming extra bone is called heterotopic ossification. It typically begins in infancy within the skin, sometimes the bone can appear like grains of rice under the skin; other times there may be larger lumps. It moves into the subcutaneous tissue (the fatty layer just beneath the skin). It can then progress into deep connective tissue, as well as in muscles, tendons, and ligaments.

(With thanks to the What is POH? Guidebook for the content on this page.  Download link below)

How is it diagnosed?

The condition is often first noted in infancy with the appearance of small “rice-grain” particles of bone in the skin that parents may describe as a rough texture. Because the condition is exceedingly rare, many medical professionals have not heard of the disease, making misdiagnosis common.

As the bone formation progresses through childhood, it moves from the skin into deeper including muscles, tendons and ligaments. This heterotopic bone appears as scattered nodules and lace-like webs that can involve small or large regions of the body. When this extra bone formation crosses a joint, it can lead to stiffness, locking, and permanent immobility.

Diagnosis is usually confirmed through clinical observations, medical imaging, and genetic testing.

How does it affect a person?

Progression is usually a gradual process., though everyone experiences different rates of new bone formation. While it is hard to predict exactly how quickly things will change for each person, we know that for some, it can happen more rapidly than for others.

POH can affect any area of the body. There is a broad spectrum of symptoms, ranging from mild cases with minimal involvement to those where a person is more significantly impacted. Some individuals have only very small areas involved, while others have more extensive bone formation. In some people, the condition can predominate on one side of the body, leading to asymmetry.

Will my POH get better?

Unfortunately, POH does not improve over time. The “P” in POH stands for Progressive, meaning the condition is likely to worsen as a person gets older. Since POH is part of a person’s genetic make-up, they are born with the condition and will not outgrow it, even if the extra bone is not present at birth.

The extra bone already produced by POH will not spontaneously disappear either. If you have POH, your body won’t make new bone all the time. You may go months or even years without apparent progression of your POH.  However, there is always a chance that extra bone will form.

Can Anything Make POH Worse?

Since POH bone often forms within the skin, even a common bump or fall can cause irritation at the site. Occasionally, this may lead to a piece of bone breaking through the skin’s surface. Unlike other conditions, POH does not typically cause large “flare-ups” with severe swelling; however, a serious injury to soft tissue can still trigger new bone growth in that specific area.

Medical interventions can also be a trigger, so caution is required with certain procedures. Surgery to remove POH bone is generally avoided because the trauma often causes bone to grow back more aggressively. Therefore, any surgery must only be carried out after careful consultation with a POH specialist. Similarly, routine injections or blood tests should only be performed in ‘clear’ areas of the body where no POH bone is present.

While POH seems to progress slowly most of the time, it is currently unclear why the disease is active at certain times and “quiet” at others.

For a comprehensive discussion, please consult a medical professional or download the What is POH? Guidebook.

Is there a treatment for POH?

Currently, there is no cure or treatment for POH that stops new bone formation. However, patients can still receive vital support from specialist medical teams, who focus on appropriate therapies and effective pain management. It is also important to take care of your emotional wellbeing too.

To stay connected with the latest research and potential breakthroughs, get in touch with FOP Friends, or reach out directly to the Progressive Osseous Heteroplasia Association (POHA).

Is there a specialist support group for patients with POH and their families?

Because POH is extremely rare (with fewer than ten known families in the UK), there is currently no dedicated POH-specific $\text{organisation}$.

The UK FOP Community Invitation

Individuals and families affected by POH are warmly invited to join the UK FOP community – FOP Friends!

* Shared Challenges: Many of the challenges, resources, and medical professionals are the same for both POH and FOP.

* Support Channels: We would be happy to include you in our FOP Families UK closed Facebook page and our WhatsApp group.

* Events: You are also welcome to attend any of our community events. We believe we are #StrongerTogether.

Please get in touch so we can discuss the best ways for you to connect with the community.

International Support

Families can also contact two established international organisations:

POH Disease $\text{Organisation}$ (America): www.pohdisease.org

International FOP Association (IFOPA): www.ifopa.org

We have produced a short reel of facts and information about POH.   This is useful for raising awareness of POH.

You can view it here: What is POH?

The guidebook “What is POH? A Guidebook for Families” (Second Edition 2002) by Prof. Fred Kaplan, Prof. Eileen Shore et al.

This is an invaluable guide for anyone looking for an introduction to the condition.

Credit: The POH Association

Download the full guide here…

A quick guide for kids. Useful for introducing POH to kids, their siblings, or friends.

For a copy, please contact us: FOP Friends

We have compiled a list of medical specialists primarily experienced in FOP. Since the conditions share similar challenges, many of these doctors and specialties, who represent a wide national and international network, also have expertise and insight into POH.

Contact us for a copy: FOP Friends