[Prenatal diagnosis of osteogenesis imperfecta. Two cases].

We report two cases of prenatal diagnosis of osteogenesis imperfecta (type S of Marotaux), diagnosed at 23 and 24 weeks of gestation, revealed by of an ultrasound scan which noted an abnormal femoral incurvation. The problem of differential diagnosis with other diseases causing femoral incurvation (notably campomelic dysplasia) is difficult, especially at early stage. This question is debated here. The interest to associate ultrasound scan and uterine contents radiography is so demonstrated.