SP7 and osteogenesis imperfecta: Novel variants of the OSX/Sp7 gene have been identified as a cause of recessive osteogenesis imperfecta, a disorder characterized by bone fragility and hearing impairment.33 Sp7/Osx regulates and influences zebrafish larval tooth development and bone mineralization.34 During osteoblast differentiation, the molecular switch OSX/Sp7 plays a crucial role in the formation of active chromatin states.35 Mice lacking Sp7 are unable to express osteoblast-associated genes such as SPARC(secreted protein, acidic and rich in cysteine), Spp1(secreted phosphoprotein 1)/osteopontin, BSP.