To understand the salient features of skeletal dysplasias at antenatal ultrasound. To differentiate between the lethal and non-lethal skeletal dysplasias at morphology scanning. To review the classification of skeletal dysplasias, and features seen in the most common and recognizable dysplasias.

Skeletal dysplasias are characterized by abnormalities of cartilage and bone growth, resulting in abnormal shape and size of the skeleton, and disproportion of the long bones, spine, and head. The prevalence of skeletal dysplasias is 1 in 2000 to 1 in 5000 births1. While there are many skeletal dysplasias, four disorders comprise almost 70%: achondroplasia, thanatophoric dysplasia, osteogenesis imperfecta, and achondrogenesis. Around 25% of neonates with a skeletal dysplasia are still born, and one third die in the first week of life2, causing enormous stress...

The Diagnosis of a Skeletal Dysplasia. A skeletal dysplasia is usually suspected when the antenatal ultrasound shows disproportionately short limbs compared with the size of the head and body. There are over 350 different types of skeletal dysplasias3, and there are other conditions such as aneuploidies that can mimic these diseases. Investigation of a suspected skeletal dysplasia should begin with a detailed ultrasound scan, including measurements of all the long bones, the head, chest and abdomen, as well as detailed imaging of the spine and...

The appropriate identification of skeletal dysplasias is important not only for current pregnancy management, but also for genetic counselling concerning future pregnancies.

Dr Sarah Constantine MBBS, FRANZCR, Senior Perinatal Radiologist, Department of Medical Imaging, Women’s and Children’s Hospital, South Australia. Associate Professor Lynette Moore BMBS, FRCPA, Paediatric Pathologist, SA Pathology, Women’s and Children’s Hospital, South Australia.

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