Moreover, we identified a series of new mutations in both genes: substitution of guanine for thymine in exon 9 in patient no. 2 and deletion of 10 nucleotides in exon 50 (frameshift) adjacent to a missense mutation (substitution of glutamine by valine) in OI patient no. 4, both in the COL1A1 gene. Here, COL1A1 is linked to osteogenesis imperfecta.