COL1A1 and osteogenesis imperfecta: A study in children and adolescents with OI type I caused by COL1A1 haploinsufficiency mutations suggested that the rate of femur and tibia fractures was about 90 times higher than in their healthy peers.37 In adults with OI, it has been estimated that the incidence of femoral shaft fractures is about 35 times higher than in the general population.38