Although a retinoic acid receptor γ agonist (palovarotene) was approved for treating FOP in Canada and an anti-Activin A antibody (REGN 2477), an immunosuppressant (rapamycin), and ACVR1 kinase inhibitors (IPN60130), are currently in clinical trials, use of these drugs is limited14. The gene discussed is ACVR1; the disease is fibrodysplasia ossificans progressiva.