Orthotics Orthotics often are used to stabilize lax joints, such as the ankle and subtalar joints, and to prevent progressive deformities and fractures. 10 Commonly used devices include ankle-foot, knee-ankle-foot, and forearm orthoses. The role of orthotics in the bisphosphonate era needs to be reevaluated. Future Directions Future advances are likely to include the identification of additional genes that cause osteogenesis imperfecta. New insights into the primary and secondary genetic consequences of the mutations should provide a better understanding of the pathogenesis of osteogenesis imperfecta and its related and overlapping syndromes. The latter advances will enable the classification of osteogenesis imperfecta to be improved and enable treatment trials to be stratified accordingly. The treatment options also are likely to expand with new or modified pharmaceutical, cell therapy, and gene therapy protocols. As these advances occur, it is likely that the role of surgery, orthotics, and physical therapy will diminish. Glossary COL1A1 = the gene encoding the pro-[alpha]1(I) protein chain. COL1A2 = the gene encoding the pro-[alpha]2(I) protein chain. Gly-X-Y = the repeating amino acid triplet of the helical domain of the collagen chains in which GLY is the amino acid glycine whereas X and Y can be any amino acid. Pro-[alpha]1(I) and pro-[alpha]2(I) = the proteins chains of Type I collagen.