Antenatal diagnosis of lethal osteopetrosis.

We describe a case of the lethal form of osteopetrosis diagnosed prenatally by ultrasonography. Anomalies detected on ultrasound examination at 18 weeks' gestation included skeletal hyperdensity, communicating hydrocephalus and short long bones. At 21 weeks' gestation, cordocentesis was performed to measure the levels of calcium, phosphorus and alkaline phosphatase. The fetus was aborted at 22 weeks' gestation. The diagnosis of osteopetrosis was confirmed by postmortem radiological and histopathological analysis.