Fop

Fibrodysplasia ossificans progressiva (FOP) is a rare and disabling genetic disorder characterized by the abnormal development of bone in muscles, tendons, and ligaments. This condition is also known as Stone Man Syndrome.

Signs and symptoms

The primary symptom of FOP is the progressive formation of bone in areas where bone is not normally present, such as within muscles, tendons, and ligaments. This process, known as heterotopic ossification, leads to restricted movement and can cause significant disability. Other symptoms may include malformed big toes, which are often present at birth.

Causes

FOP is caused by a mutation in the ACVR1 gene, which encodes the activin A receptor type I. This mutation leads to inappropriate activation of the receptor, causing the abnormal bone formation.

Diagnosis

Diagnosis of FOP is primarily based on clinical evaluation and the presence of characteristic symptoms, such as malformed big toes and progressive heterotopic ossification. Genetic testing can confirm the diagnosis by identifying the ACVR1 gene mutation.

Treatment

There is currently no cure for FOP. Treatment focuses on managing symptoms and preventing complications. This may include the use of corticosteroids to reduce inflammation, physical therapy to maintain mobility, and surgical interventions to remove heterotopic bone, although surgery is generally avoided due to the risk of exacerbating the condition.

Prognosis

FOP is a progressive condition, meaning it worsens over time. The formation of heterotopic bone can severely restrict movement and lead to complications such as difficulty breathing and eating. The life expectancy of individuals with FOP is reduced, with many patients succumbing to complications in their 40s.

Epidemiology

FOP is an extremely rare disorder, affecting approximately 1 in 2 million people worldwide. It affects both males and females equally and has no known ethnic or geographical predilection.

See also

• Genetic disorder
• Heterotopic ossification
• Orthopedics