Mutated ALK2 from FOP patients can directly convert mature endothelial cells into multi-potent mesenchymal cells, and sensitize mesenchymal cells to BMP-induced osteoblast differentiation [117, 127], thus making ALK2 a putative therapeutic target to prevent HO in FOP patients. This evidence concerns the gene ACVR1 and fibrodysplasia ossificans progressiva.