Fibrodysplasia Ossificans Progressiva
Fibrodysplasia Ossificans Progressiva is a rare genetic disorder in which connective tissue and muscle tissue are gradually ossified. Extra-skeletal bone formation causes progressive loss of mobility. The process starts in early childhood and often forms a pattern starting with the neck and shoulders and proceeding down the body into the limbs. Ossification happens spontaneously or after trauma. The prevalence is approximately 1:2.000.000 and no ethnic, racial or geographic predisposition has been described.
Trauma is an important factor in heterotopic ossification in FOP, therefore (intramuscular) injections, biopsies, and other invasive procedure are strongly advised against.
A mutation in activin receptor IA/ activin-like kinase 2 (ACVR1/ALK2), a bone morphogenetic protein (BMP) type I receptor, is the cause of all sporadic and familial cases of classic FOP.
