ACVR1 and fibrodysplasia ossificans progressiva: As the role of inflammation and of the immune system is relevant for FOP pathogenesis, it is very interesting to note that the structural and functional features of the 3′UTR sequence of ACVR1/Alk-2, are reminiscent of what is observed for genes encoding cytokines or molecules involved in inflammation pathways, thus suggesting for ACVR1/Alk-2 expression similar mechanisms of regulation.