Genetic and biochemical analyses of Israeli osteogenesis imperfecta patients.

Osteogenesis imperfecta (OI) is clinically characterized by abnormal bone fragility, with most patients harboring heterozygote germline mutations in the COL1A1 or COL1A2 genes that encode the chains of type I procollagen, the major protein in bone. More than 250 mutations in both genes in OI patients have been reported, mostly missense mutations affecting glycine residues in the triple helical domains of the two chains. These mutations disrupt protein folding and structure, and their effects often can be detected by the analysis of proteins synthesized but cultured fibroblasts or, less often, osteoblasts.