[Osteogenesis imperfecta. Classification with new aspects for pathogenesis and therapy (author's transl)].

The current state of knowledge about osteogenesis imperfecta (O. i.) is reported. According to the course of the disease and the time of onset of first sym8ptoms two types of O. i may be recognized: O. i congenita (O. i. c.) and tarda (O. i. t.). O. i. c. is associated with a more severe course which may lead to extreme skeletal deformities. O. i. t. is characterized by a much milder course. It may exist almost unrecognized. Recent biochemical investigations of collagen revealed that in O. i. quantitative and qualitative abnormalities exist in the synthesis of collagen. Abnormally synthesized collagen is produced in total amounts less than normal. This fact leeds to changes of the physical properties of the connective tissue in cases of O. i. The letest attemp to treat O. i. is the application of calcitonin. This is expected to improve the mineralisation of the skeleton and to decrease the fragility of bones. So far, only reports about shortterm follow-ups during this treatment have been reported. Therefore, a conclusive statement about the validity of therapy with calcitonin can as yet not be given.