Fibrodysplasia ossificans progressiva specialist FOP assessment
Fibrodysplasia ossificans progressiva, often shortened to FOP, is an extremely rare genetic condition where bone forms outside the skeleton in soft tissues such as muscles, tendons, ligaments and fascia.
FOP requires careful specialist input because trauma, injections, biopsies or surgery can sometimes trigger flare-ups and new bone formation.
FOP causes extra bone to form in places where bone should not normally develop.
In FOP, soft connective tissues can gradually be replaced by bone through a process known as heterotopic ossification. This extra bone can form across joints and restrict movement over time.
The condition is usually linked to a change in the ACVR1 gene. Many people with classic FOP have abnormal great toes from birth, and flare-ups often begin in childhood. In adulthood, specialist care may focus on diagnosis confirmation, flare-up history, mobility, complications, trauma avoidance and access to rare disease expertise.
- Specialist assessment of suspected or confirmed FOP
- Review of flare-ups, heterotopic ossification, imaging and mobility restriction
- Advice on avoiding procedures or injuries that may trigger new bone formation
- Support with long-term rare bone disease care and research pathways where relevant
What FOP can look like
FOP can vary between individuals, but it is typically marked by episodes of painful swelling or flare-ups followed by the formation of extra bone in soft tissues. Over time, this can restrict movement and affect daily life.
Flare-ups
Painful swelling, warmth, stiffness or reduced movement may occur during inflammatory flare-ups.
Extra bone formation
New bone can form in muscles, tendons, ligaments and other connective tissues.
Restricted movement
Bone bridges across joints can progressively limit mobility and independence.
Abnormal great toes
Short, malformed or inward-turning great toes are an important early clue in classic FOP.
Jaw or neck stiffness
Restriction may affect the jaw, neck, shoulders, back, hips or other regions depending on disease pattern.
Trauma sensitivity
Falls, bruising, injections, surgery or invasive procedures may trigger new flare-ups in some patients.
Why FOP happens
FOP is usually caused by a change in the ACVR1 gene, which affects signalling involved in bone formation. This can cause bone to form in soft tissues where it should not normally develop.
Most cases occur as a new genetic change, although the condition can be inherited. Because FOP is extremely rare, specialist review is important to reduce the risk of misdiagnosis and avoid harmful procedures.
How FOP is assessed
Diagnosis is usually based on the clinical pattern, toe findings, flare-up history, imaging and genetic testing where appropriate. Biopsy is generally avoided because trauma can trigger further bone formation.
A specialist assessment can help review previous investigations, clarify whether the pattern fits FOP and advise on safe monitoring, referral pathways and practical precautions.
FOP care is built around protection, planning and specialist coordination
There is currently no simple cure for FOP. Management focuses on reducing avoidable triggers, planning care safely, supporting mobility, managing flare-ups and coordinating input from clinicians familiar with rare bone disease.
This is especially important before dental work, injections, surgery, physiotherapy, imaging or any procedure that could involve trauma to soft tissues.
Related treatments and services
Fibrodysplasia ossificans progressiva is a rare and complex bone condition that needs careful specialist review. Assessment may include symptoms, mobility, flare history, scan findings, blood results and wider planning to reduce avoidable risks.
A specialist consultation for suspected or confirmed FOP
Professor Keen will review your diagnosis, symptoms, flare-up history, imaging, genetic testing where available, mobility limitations, previous procedures, medication history and any rare disease specialist input to date.
The consultation can help clarify the diagnosis, identify risks, advise on safer care planning and consider whether onward specialist rare disease or research-linked pathways may be appropriate.
FOP questions
Common questions from patients and families affected by fibrodysplasia ossificans progressiva.
What is fibrodysplasia ossificans progressiva?
FOP is an extremely rare genetic condition where bone forms outside the normal skeleton in soft tissues such as muscles, tendons, ligaments and fascia.
Why is trauma important in FOP?
Trauma such as injections, falls, bruising, surgery or biopsy can sometimes trigger flare-ups and new bone formation. This is why careful specialist planning is essential.
Can FOP be mistaken for other conditions?
Yes. FOP can be misdiagnosed, especially early on. Abnormal great toes, flare-up pattern, imaging and genetic testing can help support the diagnosis.
Can extra bone in FOP be removed surgically?
Surgery is usually avoided unless there is a very specific specialist reason, because trauma from surgery can trigger further bone formation.
When should I seek specialist advice?
Specialist advice is important if FOP is suspected or confirmed, especially before injections, surgery, dental procedures, physiotherapy or other interventions that may involve soft tissue trauma.
Arrange a specialist FOP and rare bone disease appointment
If you have suspected or confirmed FOP, unexplained heterotopic ossification, flare-ups, abnormal great toes or concerns about safe care planning, please contact the practice.
Contact details
For private appointments and general enquiries, please contact the office.