Several mouse models representing different mutations and OI disease severities have been challenged with genetic or pharmacological inhibition of myostatin alone or in combination with other TGF-β ligands including activin A (DiGirolamo et al., 2015; Oestreich et al., 2016a,b; Jeong et al., 2018a,b; Tauer and Rauch, 2019). The gene discussed is MSTN; the disease is osteogenesis imperfecta.