Suspected fetal skeletal malformations or bone diseases: how to explore.

Skeletal dysplasias are a heterogeneous and complex group of conditions that affect bone growth and development and result in various anomalies in shape and size of the skeleton. Although US has proved reliable for the prenatal detection of skeletal abnormalities, the precise diagnosis of a dysplasia is often difficult to make before birth (especially in the absence of a familial history) due to their various phenotypic presentations, the variability in the time at which they manifest and often, the lack of precise molecular diagnosis. In addition to the accuracy of the antenatal diagnosis, it is very important to establish a prognosis. This is a clinically relevant issue as skeletal dysplasias may be associated with severe disability and may even be lethal. We will therefore describe the respective role of two-dimensional (2-D) US, three-dimensional (3-D) US and CT in the antenatal assessment of skeletal malformations.