Osteogenesis imperfecta.

Major advances have occurred in the classification of OI and in the definition of underlying molecular defects. A clearer understanding of the pathogenesis of OI and of the relationships between the phenotypes and genotypes should emerge. The study of induced mutations in selected regions of the collagen genes with expression in cultured cells or transgenic mice should hasten this process. These advances will also provide a basis for studies into the large number of other genetically determined connective tissue disorders that are grouped together as the skeletal dysplasias. The results of recent studies in OI are providing a unique insight into many aspects of collagen and connective tissue biochemistry, physiology and pathology.