Isolation and characterization of bone cells from a patient with osteogenesis imperfecta type 1b.

The metabolic defect(s) in bone cells which manifests itself in the disease osteogenesis imperfecta (OI) type 1 is not known. Since this form of the disease displays both a variable tissue involvement and the possibility of remission it is difficult to attribute its expression to a primary mutation in the structural gene for type I collagen (as can the perinatal lethal forms of OI). In an attempt to more fully understand OI type 1 we have isolated and characterized a subpopulation of cells obtained from a sample of bone from a patient with OI type 1b. This subpopulation of cells has been shown to morphologically resemble the osteoblast phenotype, to contain the highest level of alkaline phosphatase of the cells isolated, to synthesize collagen, to respond to bone target hormones such as 1,25(OH)2D3 and parathyroid hormone, and to proliferate rapidly. Moreover, the response of these cells to the vitamin D metabolites, from the standpoint of growth regulation, is qualitatively different from normal bone cells. We intend to use these cells as a model system for studying the defect in OI type 1b.