Caudal regression syndrome

Caudal regression syndrome, or sacral agenesis (or hypoplasia of the sacrum), is a rare congenital disorder in which the fetal development of the lower spine—the caudal portion of the spine—is abnormal. It occurs at a rate of approximately one per 60,000 live births.

Some babies are born with only minor abnormalities, as compared to typical development, while some others have significant changes. Most grow up to be otherwise typical adults who have difficulty with walking and incontinence.