Caudal regression sequence

The caudal regression sequence describes a particular pattern of malformation which is frequently associated with maternal diabetes in pregnancy.

The sequence includes, to a variable degree:

• incomplete development of the sacrum and lumbar vertebrae; the extreme being sacral agenesis
• femoral hypoplasia - reduced growth of the caudal region
• neural tube defects, with disruption of the spinal cord distally

Clinically any of the sequelae of these may be noted, in addition to which a frequent feature is flattened buttocks.