Part of “CHAPTER 66 – RARE DISORDERS OF SKELETAL FORMATION AND HOMEOSTASIS“

Fibrodysplasia (myositis) ossificans progressiva (FOP) features accumulation of true bone in the fibrous connective tissue of striated muscle, ligaments, tendons, and fascia; however, smooth muscle is spared.2,4,5 and 6 Patients have congenital anomalies of the digits (75% incidence of bilateral microdactyly of the great toe with synostosis and hypoplasia of the phalanges), allowing a presumptive diagnosis at birth.5 The pathogenesis involves endochondral bone formation in soft tissues.54 Most cases appear to represent new mutations for this autosomal dominant disorder (advanced paternal age seems to be a causal factor).