Heterotopic Ossification in Mouse Models of Fibrodysplasia Ossificans Progressiva.

Fibrodysplasia ossificans progressiva (FOP), a rare genetic disorder of progressive extra-skeletal ossification, is the most disabling form of heterotopic ossification (HO) in humans. Most people with FOP carry an activating mutation in a BMP type I receptor gene, ACVR1 R206H, that promotes ectopic chondrogenesis and osteogenesis and in turn HO. Advances in elucidating the cellular and molecular events and mechanisms that lead to the ectopic bone formation are being made through the use of genetically engineered mouse models that recapitulate the human disease. We describe methods for inducing heterotopic ossification in a mouse model that conditionally expresses the Acvr1 R206H allele.