Fibrodysplasia Ossificans Progressiva

Date of submission: 04-12-2020 | Date of acceptance: 16-03-2021 | Published: 03-10-2021

Abstract

Fibrodysplasia ossificans progressiva (FOP) is an extremely rare disease with an estimated prevalence of 1/2000000. Classic FOP is caused by a recurrent activating mutation in the gene ACVR1 / ALK2. It has an autosomal dominant transmission pattern but  in most cases occurs spontaneously. (1)

Patients with classical FOP are initially asymptomatic, presenting only characteristic congenital malformations of the great toes (1). In the first decade of life it manifests as acute sporadic episodes of painful soft tissue sweling. Although some exacerbations spontaneously regress, some develop heterotopic ossification of the affected soft tissues.(2)

Over time these extra articular heterotopic formations condition the child’s mobility, having a cumulative effect, conditioning the development of thoracic insufficiency syndrome, reducing markedly life expectancy. (3)

We present a case of a 13-year-old boy, born in Guinea Bissau, referred to a pediatric hospital at the age of 2, for evaluation and clinical follow-up in the context of sporadic episodes of generalized pain and dispersed swellings.  He was diagnosed with FOP, with genetic testing confirmation.

In the following years he had multiple sporadic episodes of painfull soft tissue swelling, which often progressed to stiffness and decreased mobility of the affected joints. The disease predominantly affected both elbows, both coxo femoral articulations and the dorsal spine.

We present two images documenting the progression of the disease over the years, figure 1 and 2, we can verify ill-defined radio-opaque neoformations in the upper left limb and coxo femoral joints, and its expansion over time conditioning rigid ankylosis of the affected joints.