FN1 and osteogenesis imperfecta: In the majority of EDS and in ATS fibroblasts carrying mutations in different ECM-related genes, but not in those derived from LDS, MFS and OI patients, the FN–ECM and the α5β1 integrin are disorganized and strongly reduced respectively and, consequently, the alternative FN receptor the αvβ3 integrin, which is almost absent in control fibroblasts, is recruited.