The ideal kinase inhibitor for treatment of FOP without possible on-target side-effects in other tissues is one that specifically targets mutated ALK2, inhibiting the extra activity of ALK2 derived from the FOP allele, while also not affecting ALK1, ALK3, ALK6, and wild-type ALK2 kinase activity. Here, ACVR1 is linked to fibrodysplasia ossificans progressiva.