Osteogenesis imperfecta (OI) is a group of heritable diseases of the connective tissues characterized by tissue fragility and skeletal deformities. Heterogeneous mutations in the genes encoding type I collagen underlie the majority of OI cases. The studies reviewed here highlight the potential for new therapeutic strategies, diagnostic techniques, molecular research, and characterization of bone tissue parameters across the spectrum of OI. Recent developments in genetic and molecular biologic approaches are providing new insights regarding OI pathogenesis, diagnosis, and treatment strategies. With respect to therapies, the use of bisphosphonates to treat OI appears to be the most promising for the short term. The potential for bone marrow transplants is also encouraging, but significant challenges need to be overcome before this can be considered as a universal clinical option. (C) 2000 Lippincott Williams and Wilkins, Inc.