Spondylocostal dysostosis is a group of conditions characterized by abnormal development of bones in the spine and ribs. The bones of the spine (vertebrae) are misshapen and abnormally joined together (fused). Many people with this condition have abnormal side-to-side curvature of the spine (scoliosis) due to malformation of the vertebrae. In addition to spinal abnormalities, some of the rib bones may be fused together or missing. Affected individuals have short, rigid necks and short torsos because of the bone malformations. As a result, people with spondylocostal dysostosis have short bodies but normal-length arms and legs, called short-trunk dwarfism.

Mutations in several genes are known to cause spondylocostal dysostosis. The most common form of the condition, spondylocostal dysostosis type 1, is caused by mutations in the DLL3 gene. Mutations in other identified genes each account for a small number of cases of the condition.

Spondylocostal dysostosis is a rare condition, although its exact prevalence is unknown.

Spondylocostal dysostosis can have different inheritance patterns. Most types, including type 1, are inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. The parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but they typically do not show signs and symptoms of the condition. Other types of spondylocostal dysostosis are inherited in an autosomal dominant pattern. Autosomal dominant inheritance means that one copy of an altered gene in each cell is sufficient to cause the disorder. The signs and symptoms of spondylocostal dysostosis are typically more severe with autosomal recessive inheritance.

Published Date: June 01, 2016
Published By: National Institutes of Health