What is skeletal dysplasia?
Skeletal dysplasia is a term used to describe a group of several hundred conditions that affect the formation and growth of a baby’s bones and cartilage. Some of the conditions result in the child’s arms, legs, and head being disproportionate in size when compared with the torso. These abnormalities may result in the child having a very short stature, or “dwarfism.” In some types of skeletal dysplasia the bones may become demineralized, or brittle, causing them to break easily, even before birth, and often the abnormal bone formation can lead to abnormal bone shapes.
Certain skeletal dysplasia conditions can be fatal. These deaths occur when the bony chest cavity fails to grow normally, preventing normal lung development and resulting in lungs that are too small to support the baby’s breathing after birth—a condition known as ‘lethal pulmonary hypoplasia’.
Here are some of the more common types of skeletal dyplasia:
- Achondroplasia is a type of short-limbed dwarfism. Children with acondroplasia have short forearms and legs, a large head, and an average-sized torso. The condition, which occurs in about 1 in 40,000 births, does not affect the child’s intelligence or lifespan.
- Osteogenesis imperfecta, sometimes called “brittle bone disease,” is a term that encompasses a group of conditions characterized by bones that break easily, sometimes from no obvious cause. The conditions range from mild to severe, and may or may not result in a curved spine and small stature. Milder forms of osteogenesis imperfecta do not affect the child’s lifespan.
- Achondrogenesis is a group of skeletal dysplasia conditions that severely affect bone formation. In addition to having short arms and legs, babies with achondrogenesis have a small, narrow chest and underdeveloped lungs. As a result, these babies usually die before birth or soon afterwards.
- Campomelic dysplasia is a usually lethal skeletal dysplasia typified by severe bowing of the long bones. It is also associated with disorders of sexual development as it is caused by genetic mutations that affect the development of both cartilage and the testes.
- Short-rib polydactyly syndrome is a group of skeletal dysplasia conditions in which the growth of the baby’s bones is severely affected, resulting in short arms and legs, short ribs, and more than the normal number of fingers and/or toes. Because of their small, narrow chests, all babies with short-rib polydactyly syndrome have severe pulmonary hypoplasia, which prevents their survival after birth.
Each of the hundreds of skeletal dysplasia conditions is relatively rare, but collectively they affect about 1 in 4,000 births.
Who will be on my care team?
At the Midwest Fetal Care Center, a collaboration between Children’s Minnesota and Allina Health, we specialize in individual attention that starts with you having your own personal care coordinator to help you navigate your baby’s treatment process. We use a comprehensive team approach to skeletal dysplasia and any associated conditions. That way, you are assured of getting the best possible information by some of the most experienced physicians in the country. For skeletal dysplasia, your care team will include a maternal-fetal medicine specialist, a neonatologist, a geneticist, a nurse specialist care coordinator, a perinatal social worker, and several other technical specialists. This comprehensive team will follow you and your baby closely through the evaluation process and will be responsible for designing and carrying out your complete care plan.