Short answer · Medically reviewed summary · Last updated: 2026-05-08
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic condition caused by a specific mutation in the ACVR1 gene, which leads the body to mistakenly repair damaged muscle and connective tissue with bone rather than scar tissue. This process, known as heterotopic ossification, results in the formation of a second skeleton that progressively restricts movement throughout the body. What causes Fibrodysplasia ossificans progressiva? The primary cause of Fibrodysplasia ossificans progressiva is a gain-of-function mutation in the ACVR1 gene.
Which are the causes of Fibrodysplasia ossificans progressiva?
Causes of Fibrodysplasia ossificans progressiva explained: genetic and environmental factors, reviewed against medical sources, plus patient perspectives.
Fibrodysplasia ossificans progressiva (FOP) is a rare genetic condition caused by a specific mutation in the ACVR1 gene, which leads the body to mistakenly repair damaged muscle and connective tissue with bone rather than scar tissue. This process, known as heterotopic ossification, results in the formation of a second skeleton that progressively restricts movement throughout the body.
What causes Fibrodysplasia ossificans progressiva?
The primary cause of Fibrodysplasia ossificans progressiva is a gain-of-function mutation in the ACVR1 gene. In a healthy body, this gene helps regulate the growth and development of bones and cartilage. In individuals with Fibrodysplasia ossificans progressiva, the mutated gene acts like a "stuck" switch, misinterpreting the body's repair signals and instructing muscle and soft tissue to transform into bone instead of healing normally.
Is Fibrodysplasia ossificans progressiva hereditary?
While Fibrodysplasia ossificans progressiva is a genetic disorder, the vast majority of cases occur as a "de novo" or spontaneous mutation, meaning it is not inherited from parents. The mutation typically happens at the moment of conception. Because the condition is autosomal dominant, an affected individual has a 50% chance of passing the mutation to their offspring, though most diagnosed cases arise without a family history.
What triggers the bone growth in FOP?
While the genetic mutation is the underlying cause, environmental triggers often initiate the "flare-ups" that lead to new bone formation. These triggers are critical to understand for disease management:
- Soft tissue injury: Bumps, bruises, or muscle strains.
- Viral illnesses: Common infections like the flu or COVID-19 can trigger systemic inflammation.
- Surgical procedures: Attempting to remove heterotopic bone surgically often causes the body to grow even more bone in response.
- Intramuscular injections: Needles penetrating the muscle can act as a catalyst for ossification.
What is the current state of research?
Scientists are actively researching the underlying pathophysiology of Fibrodysplasia ossificans progressiva to develop therapies that can "turn off" the misdirected bone growth signal. Current research focuses on understanding the molecular pathways controlled by the ACVR1 gene to prevent the inflammatory triggers from resulting in permanent skeletal transformation.
Next steps
- Consult a clinical geneticist to confirm a diagnosis of Fibrodysplasia ossificans progressiva through genetic testing.
- Connect with the Fibrodysplasia ossificans progressiva community at DiseaseMaps.org to share experiences with the 49 other members.
- Avoid intramuscular injections and elective surgeries whenever possible to minimize flare-up risks.
Medical disclaimer: This information is for educational purposes and should not replace professional medical advice, diagnosis, or treatment.
References
- NIH Genetic and Rare Diseases Information Center (GARD)
- Orphanet: Rare Disease Database
- OMIM (Online Mendelian Inheritance in Man): #135100
- International FOP Association (IFOPA)
