Mutations of c.874G>A (p. Gly292Ser), c.647G>A (p. Arg216His), and c.2341G>C (p. Gly781Arg) of the COL1A2 gene led to a mild course of the disease with type I of OI; c.2461G>A (p. Gly821Ser), c.2569G>T (p. Gly857Cys) mutations of the COL1A1 gene and c.2756G>A (p. Gly919Asp), c.3277G>A (p. Gly1093Ser) mutations of the COL1A2 gene to type III; and mutation c.2971G>C (p. Gly991Arg) of the COL1A2 gene to type IV of OI. The gene discussed is COL1A2; the disease is osteogenesis imperfecta.