COL1A1 and osteogenesis imperfecta: In this work, the analysis of COL1A1 and COL1A2genes in five unrelated patients with type I and type III OI identified a total of 8 novel mutations, whereas the analysis from miR-29b expression led us to propose that it does not regulate COL1A1 levels during osteoblast differentiation in OI in comparison to normal mesenchymal stem cells.