COL1A2 and osteogenesis imperfecta: In the Col1a2+/p.G610C OI mouse model, bone marrow stromal cells had a much‐reduced ability to form mature osteoblasts compared to controls6 and in vivo, recent studies have shown the maturation and trans‐differentiation of hypertrophic chondrocytes to osteoblasts is significantly reduced, resulting in the reduced growth of the OI bones.26, 27