VUmc is committed to the care and scientific research of a rare connective tissue, muscle and bone disease: Fibrodysplasia Ossificans Progressive (FOP)
FOP, or Fibrodysplasia ossificans progressiva, is a rare connective tissue disease, whereby muscles, tendons and ligaments are gradually converted into bone. The extraskeletal bone formation causes progressive loss of mobility by forming bridges and thereby 'locked' joints. Eventually, a patient becomes trapped in its own armor, a so called second skeleton. The disease is progressive and characterized by episodic exacerbations ('flare-ups') which are often succeeded by new extraskeletal bone formation.
The genetic cause of the disease is known since 2006. The mutation, a missense mutation, is located in the Activin A receptor type 1 (ACVR1), which encodes a type I bone morphogenic protein (BMP) receptor, and is involved in the differentiation of cells. And is assumed to drive inappropriate bone formation as a result of receptor hyperactivity. After birth the only sign of FOP may be a malformed big toe. The understanding of the disease, however, is limited and therapeutic options are not available. Close collaboration internationally, scientifically and with patient organizations will improve the knowledge and thereby treatment options for patients with FOP.