Background: Fibrodysplasia ossificans progressiva (FOP) is a rare and disabling heritable connective tissue disease that is difficult to treat. This study seeks to explore the clinical characteristics, clinical manifestations, treatment and prognosis of FOP to provide a clinical basis for its early diagnosis and treatment.

Methods: Twenty-six children with FOP were retrospectively analyzed in terms of their onset, clinical manifestations, auxiliary examinations and treatment.

Results: Among the 26 cases, the youngest age of manifestation of mass was 8 days after birth, and the average age was 3 years and 2 months. The peak age was 2-5 years old. Inflammatory mass and toe-finger deformity are the main early clinical manifestations of the disease. These inflammatory masses often lead to hard osteogenic deposits that initially mainly involve the central axis, such as the neck (22/26, 84.6%), back (20/26, 76.9%), and head (13/26, 50%). Toe-finger deformity mainly manifests as symmetrical great toe deformity, or short and deformed thumb and little finger. The diagnosis of FOP requires typical clinical manifestations or ACVR1 gene detection. The main therapeutic drugs for FOP include glucocorticoids and non-steroidal anti-inflammatory drugs. Although not compliant with the recommended medical management of FOP, in our clinical practice children with uncontrollable illness could be treated using a variety of immunosuppressive agents in combination.