Osteogenesis Imperfecta type II with the variant c.4237G>A (p.Asp1413Asn) in COL1A1 in a dichorionic, diamniotic twin pregnancy

We present the case of a 34-year-old woman with a prenatally diagnosed osteogenesis imperfecta type II of one fetus of a diamniotic-dichorionic twin pregnancy at 28 weeks and 2 days of gestation. The diagnosis was suspected after a routine ultrasound examination, specified by 3D-ultrasound and confirmed with moleculargenetic analyses of COL1A1 with DNA of fetal cells obtained after amniotic drainage. Since a premature rupture of membranes occurred a cesarean section was performed at 36 weeks of gestation. Both newborns received primary medical care by neonatologists. The affected child received further treatment initially stationary, later as an ambulant patient. Even though ultrasound is a powerful tool to identify clinical features of osteogenesis imperfecta, the condition can finally only be confirmed by collagen or DNA analyses. We discuss the possibilities and limits of prenatal diagnosis, treatment options as well as issues that are relevant for genetic counseling.