[Prenatal and neonatal diagnosis of osteogenesis imperfecta in obstetrical practice].

Osteogenesis imperfecta (OI types I, II, III, IV) is a heterogeneous group of genetically disorders of connective tissue. Quantitative or qualitative abnormalities of type I collagen form pathogenetical basis of the disease. They are caused by mutations in genes encoding collagen proteins or enzymes involved in collagen biosynthesis. The clinical features of each type usually correspond to the type of mutation. Typical manifestations are fragile bones with multiple bone fractures and bone deformities. Currently applied diagnosis in utero of OI II and sometimes OI III may be performed. Diagnosis of other OI phenotypes cannot be made until after birth. We present three cases of OI II (four children) diagnosed, in utero, by ultrasound examination. The analysis in work include: 1. the prenatal sonographic features of OI type II 2. the biochemical properties of collagen in the above cases 3. genetic counselling of the families affected by OI.