The purpose of this study is to collect urine samples from patients with fibrodysplasia ossificans progressiva (FOP) for the assessment of biomarkers related to disease, disease progression and for prediction of flare-ups of the disease. Disease related biomarkers in these patients are currently unknown. This study aims to support the development of novel therapy/ies for this disease.

Inclusion Criteria:

• Male and female patients ≥ 5 and ≤ 35 years of age with a diagnosis of FOP.
• Physically able to provide first-morning urine sample of at least 30 mL
• Able to communicate well with the investigator, to understand and comply with the requirements of the study
• About half of the patients enrolled should have a flare-up, which is defined as an acute exacerbation of disease activity characterized by two or more of the following symptoms: pain, swelling, decreased range of motion, impaired function

Exclusion Criteria:

• Diagnosis of diabetes
• Diagnosis of other systemic inflammatory disorder (juvenile idiopathic arthritis, systemic lupus erythematosus, etc.)
• Diagnosis of cancer other than nonmelanomatous skin cancer.

Patients with Fibrodysplasia Ossificans Progressiva.