A rare case of deformity: Fibrodysplasia ossificans progressiva

Abstract

Fibrodysplasia ossificans progressiva (FOP) is a rare genetic disorder and the most debilitating condition of heterotopic ossification in humans. Misdiagnosis is common and they suffer from complications of incorrect diagnosis and subsequent inappropriate treatment hence, to create awareness, we are reporting a genetically confirmed case of FOP. A 10-year-old boy, born to a non-consanguineously married couple, presented with progressive stiffness of the neck, back, and limbs with restriction of movements. Examination showed two firm non-tender immobile swellings over the back with scoliosis towards the left side. A bilateral hallux valgus deformity with restricted movements of the great toe was noted. Outside treated as mixed connective tissue disorder without any improvement. The X-ray showed calcifications in the swellings. Genetic testing showed the pathogenic variant in the activin A receptor type 1 gene. The FOP should be considered in children presenting with progressive stiffness, deformity of the feet, and ectopic ossifications to avoid misdiagnosis and inappropriate treatment.