fibrodysplasia ossificans progressiva

Hallux valgus

A malformation of the great toes that is present from birth is a hallmark of fibrodysplasia ossificans progressiva. It often appears as the big toe turning outward, and it is one of the earliest signs of the condition.

Short hallux

A malformed, often short great toe is present from birth in FOP and is an early clue to the diagnosis, frequently before the bone formation begins.

Autosomal dominant inheritance

FOP is autosomal dominant, but almost all cases arise from a new (de novo) variant rather than being inherited from a parent.

Limitation of neck motion

Limited movement of the neck is commonly seen in fibrodysplasia ossificans progressiva. In one cohort of ten people, eight had limited neck mobility.

Ectopic ossification in ligament tissue

Ligaments are among the connective tissues that turn to bone in FOP, contributing to progressive stiffening of the joints.

Ectopic ossification in tendon tissue

In FOP the abnormal bone formation involves tendons, ligaments, fascia, and skeletal muscle, gradually replacing flexible tissue with bone.

Ectopic ossification in muscle tissue

In fibrodysplasia ossificans progressiva, bone gradually forms inside soft tissues that are not normally bony — muscle, tendons, ligaments, and fascia. This is called heterotopic ossification, and over time it leads to loss of movement and affects quality of life.

Seizure

People with fibrodysplasia ossificans progressiva can have a range of neurological symptoms, such as long-lasting pain and involuntary movements. A link with epileptic seizures has been described, though little is yet understood about it.

Synostosis of joints

Episodes of bone formation, sometimes set off by minor trauma, can fuse joints together, leading to loss of movement and severe disability in FOP.

Ectopic ossification

Flare-ups are episodes of painful swelling in the soft tissues. They often begin in early childhood and tend to progress to new bone forming in those tissues, with movement being lost step by step over time.

Limitation of joint mobility

As new bone builds up across joints, those joints can become locked in place. This has been described as progressing to a fixed jaw, hip involvement that affects walking, and eventually the need for a wheelchair.

Fibrodysplasia ossificans progressiva

Diagnosed using: clinical diagnosis from great toe malformation and heterotopic ossification.

Fibrodysplasia ossificans progressiva

Diagnosed using: ACVR1 genetic testing.

Fibrodysplasia ossificans progressiva

Diagnosed using: biopsy avoidance.

palovarotene

In clinical trials for fibrodysplasia ossificans progressiva, palovarotene significantly reduced the progression of heterotopic ossification, especially during active disease and flare-ups.

Used to help with: Fibrodysplasia ossificans progressiva.

corticosteroid flare management

For an acute flare-up of fibrodysplasia ossificans progressiva, current recommendations support starting corticosteroid therapy within 24 hours of the flare-up beginning. Starting later in the course is less likely to help.

Used to help with: Fibrodysplasia ossificans progressiva.

flare and trauma avoidance

Much of the day-to-day management of fibrodysplasia ossificans progressiva is supportive: physiotherapy to help preserve movement, and education focused on avoiding triggers and seeking care early when a flare-up begins.

Used to help with: Fibrodysplasia ossificans progressiva.

surgery avoidance

Because injury to soft tissue can set off a flare-up, the International Clinical Council on FOP generally recommends avoiding surgery in people with fibrodysplasia ossificans progressiva unless the situation is life-threatening.

Used to help with: Fibrodysplasia ossificans progressiva.

trauma

Physical injury (trauma) is a major trigger for flare-ups and new bone formation; protecting against falls and injury is an important part of care.

Reported in the research mapped here as able to provoke: Ectopic ossification in muscle tissue in people with this condition.

surgery

Surgery can provoke new heterotopic bone, so operations are avoided unless truly life-threatening and only with FOP-expert guidance.

Reported in the research mapped here as able to provoke: Ectopic ossification in muscle tissue in people with this condition.

biopsy

Biopsy of a swelling can trigger an explosive flare and new bone, so biopsies should be avoided; diagnosis is made clinically and genetically instead.

Reported in the research mapped here as able to provoke: Ectopic ossification in muscle tissue in people with this condition.

ACVR1

Fibrodysplasia ossificans progressiva is caused by mutations in the ACVR1 gene and is inherited in an autosomal dominant pattern. The condition is marked by malformed great toes present from birth and by bone forming progressively in the soft tissues.

Described as modulating: Fibrodysplasia ossificans progressiva.