Autosomal recessive spondylocostal dysostosis type 1 is a member of the heterogeneous group of disorders termed the spondylocostal dysostoses that is characterized by multiple vertebral segmentation defects and rib anomalies. Radiologically, the disease is characterized by vertebral malformations including hemivetebra, block vertebra, fused vertebra and spina bifida and deformities of the ribs that include absent ribs and bifid or fused ribs, which give the typical "crab like", or "fan like" appearance. Homozygous variants in the DLL3 gene have been associated with this disorder.