TGFB1 and osteogenesis imperfecta: Furthermore, whereas mild and moderately severe murine models of collagen-related OI (G610C Col1a2tm1.1Mcbr and Crtap–/–) have shown a response to anti–TGF-β treatment, such response has not been observed in a more severe model (Col1a1Jrt/+) that has features of Ehlers-Danlos syndrome and OI (30).