Fibrodysplasia ossificans progressiva (FOP) is among the most devastating musculoskeletal disorders. FOP is caused by activating variants in ACVR1, most often arising de novo, and is characterised by congenital malformations of the great toes, followed by episodic flare-ups and progressive heterotopic ossification in soft tissues.1,2 Lesions can be triggered by minor trauma, intramuscular injections, or surgery, but can also arise without an identifiable trigger. Over time, heterotopic bone forms a second skeleton, progressively restricting movement of the jaw, spine, hips, shoulders, and thorax.
Kaynak: The Lancet
