Fibrodysplasia ossificans progressiva in a young adult with genetic mutation: Case report.

Rationale: Fibrodysplasia ossificans progressiva (FOP) is a rare autosomal dominant disorder characterized by congenital skeletal deformities and soft tissue masses that progress into heterotopic ossification. Deformities of the great toes are distinctive and heterotrophic ossification usually begins in the first decade of the patient's life. Any invasive procedure could potentially trigger a flare and heterotopic calcification. The diagnosis is difficult and there is no effective treatment for FOP and the approximate life expectancy is 4 decades.

Patient Concerns: A 22-year-old male patient who had suffered from pain and movement limitations for 14 years. At the early stage of disease, the child underwent an operation on both thighs with a diagnosis of myophagism. He had serious stiffness and multiple bony masses with the characteristic bilateral hallux valgus deformity and microdactyly.

Diagnoses: The patient was diagnosed with FOP by the help of characteristic great toe malformations and widespread heterotopic ossification throughout the body. Deoxyribonucleic acid sequencing demonstrated that the patient had a de novo heterozygous mutation (c.617G>A; p.R206H) in activin A receptor/activin-like kinase 2.

Interventions: We administered a co-therapy of glucocorticoids, NSAIDs to relieve pain, and montelukast for 2 months. Bisphosphonate (5 mg, intravenous) was used once.

Outcomes: At the follow-up 12 months later, the patient still felt low back pain sometimes and need take NSAIDs three times a week.

Lessons: Clinicians and radiologists should realize the characteristic features of FOP and early diagnosis can prevent additional invasive harm to the patient.