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Review
. 2022 Apr 20:14:113-120.
doi: 10.2147/ORR.S337491. eCollection 2022.

Monitoring and Management of Fibrodysplasia Ossificans Progressiva: Current Perspectives

Bernard J Smilde  1   2   3 , Esmée Botman  1   2   3 , Ruben D de Ruiter  1   2   3 , Jan Maerten Smit  2   4 , Berend P Teunissen  2   5 , Wouter D Lubbers  2   6 , Lothar A Schwarte  2   6 , Patrick Schober  2   6 , E Marelise W Eekhoff  1   2   3
Affiliations
Review

Monitoring and Management of Fibrodysplasia Ossificans Progressiva: Current Perspectives

Bernard J Smilde et al. Orthop Res Rev. .

Erratum in

Abstract

Fibrodysplasia ossificans progressiva (FOP), sometimes known as myositis ossificans progressiva, is an ultra-rare disease in which bone is formed in muscular tissue, tendons and ligaments. This is known as heterotopic ossification (HO). FOP is caused by a heterozygous mutation in the highly conserved ACVR1/ALK2 gene which affects about 1 in 1.5-2 million individuals. At birth, patients with the predominant R206H mutation only exhibit a bilateral hallux valgus. During childhood, heterotopic bone formation develops in a typical pattern, affecting the axial muscles first before appendicular body parts are involved. HO can start spontaneously but is often elicited by soft tissue trauma or medical procedures. After soft tissue injury, an inflammatory process called a flare-up can start, followed by the formation of HO. HO leads to a limited range of motion, culminating in complete ankylosis of nearly all joints. As a result of HO surrounding the thorax, patients often suffer from thoracic insufficiency syndrome (TIS). TIS is the most common cause of a limited life expectancy for FOP patients, with a median life expectancy of 56 years. Management is focused on preventing soft-tissue injury that can provoke flare-ups. This includes prevention of iatrogenic damage by biopsies, intramuscular injections and surgery. Anti-inflammatory medication is often started when a flare-up occurs but has a poor basis of evidence. Several forms of potential treatment for FOP are being researched in clinical trials. Progression of the disease is monitored using CT and 18F-NaF PET/CT combined with functional assessments. Patients are regularly evaluated for frequently occurring complications such as restrictive lung disease. Here, we review the current management, monitoring and treatment of FOP.

Keywords: activin A receptor type 1; fibrodysplasia ossificans progressiva; heterotopic ossification; treatment strategies.

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Conflict of interest statement

The authors report no conflicts of interest in this work.

Figures

Figure 1
Figure 1
Bilateral, congenital malformed great toes in a 2-year-old child with fibrodysplasia ossificans progressiva. Both great toes show typical shortening and are angled inward (hallux valgus).
Figure 2
Figure 2
3D reconstruction of low-dose whole-body computed tomography scan of an adult patient with advanced FOP. There are prominent ossifications across the back, neck and chest, surrounding both hips and along the humeri leading to an altered stature and almost complete ankylosis of the joints.
Figure 3
Figure 3
Pathological pathway leading to heterotopic ossification and possible treatment strategies.
See this image and copyright information in PMC

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