Caudal regression syndrome, also k/a caudal dysplasia sequence is characterised by a series of abnormalities, including complete or partial agenesis of the sacrum and lumbar vertebrae associated with pelvic deformity. femoral hypoplasia, clubbed feet and flexion contractures of the lower extremities are also seen. CRS is often associated with anomalies of GIT, GUT, heart and NTD.

Majority of cases of CRS are sporadic. CRS is thought to arise from a defect in induction of caudal elements of the embryo before the 7th week of gestation. Prenatal diagnosis is important to discern the extent of caudal dysgenesis, so that appropriate patient counselling can be provided and post natal interventions can be planned.