Faces of Fibrodysplasia Ossificans Progressiva: Lessons from a Clinical Masquerader

Objectives To evaluate the natural history and to highlight the possible masqueraders causing diagnostic delay and iatrogenic interventions in Fibrodysplasia Ossificans Progressiva (FOP). Methods Patient details with suspected FOP were retrieved from the patient registry from 2012 through 2021. Clinical records, X-rays, clinical photographs, and molecular testing results were captured. Follow-up was recorded where available. Results A total of 16 patients with a clinical diagnosis of FOP were found. Twelve patients with both clinical and molecular records were included in this study. The median age of onset and diagnosis was 1.5 y and 6.5 y respectively with a median diagnostic delay of 3.5 y. The disease course was progressive in ten patients. Seven out of twelve patients were subjected to invasive procedures due to misdiagnosis, which exacerbated their disease progression. Conclusions Clinical suspicion followed by molecular testing is straightforward for a confirmed diagnosis of FOP. It is not only diagnostic, cost-effective, and saves time but also avoids unnecessary interventions in these patients.