Caudal Regression Syndrome

National Organization for Rare Disorders, Inc.

It is possible that the main title of the report Caudal Regression Syndrome is not the name you expected. Please check the synonyms listing to find the alternate name(s) and disorder subdivision(s) covered by this report.


  • Caudal Dysplasia
  • Caudal Dysplasia Sequence
  • Sacral Agenesis, Congenital
  • Sacral Regression

Disorder Subdivisions

  • None

General Discussion

Caudal regression syndrome is a broad term for a rare complex disorder characterized by abnormal development of the lower (caudal) end of the spine. The spine consists of many small bones (vertebrae) that collectively form the spinal column. The spinal column is generally broken down into three segments – the cervical spine, consisting of the vertebrae just below the skull; the thoracic spine, consisting of the vertebrae in the chest region; and the lumbar spine, consisting of the vertebrae of the lower back. A triangularly-shaped bony structure called the sacrum joins the lumbar portion of spine to the pelvis. The sacrum consists of five vertebrae fused together. At the end of the sacrum is the tailbone (coccyx). A wide range of abnormalities may potentially occur in infants with caudal regression syndrome including abnormal development (agenesis) of the sacrum and coccyx and abnormalities of the lumbar spine. More severe malformations may occur in some cases. Abnormalities of the lower spine can cause a variety of additional complications including joint contractures, clubfeet and disruption or damage of the end of the spinal cord may occur, potentially causing urinary incontinence. Additional anomalies of the gastrointestinal tract, kidneys, heart, respiratory system, upper limbs and upper portions of the spine can also occur. The exact cause of caudal regression syndrome is unknown. Both environmental and genetic factors are suspected to play a role in the development of the disorder.

Some sources in the medical literature classify a condition called sirenomelia as the most severe form of caudal regression syndrome. However, recently many researchers have indicated that sirenomelia is a similar, but distinct, disorder. NORD has a separate report on sirenomelia.


March of Dimes Birth Defects Foundation
1275 Mamaroneck Avenue
White Plains, NY 10605
Tel: (914)997-4488
Fax: (914)997-4763

NIH/National Institute of Neurological Disorders and Stroke
P.O. Box 5801
Bethesda, MD 20824
Tel: (301)496-5751
Fax: (301)402-2186
Tel: (800)352-9424
TDD: (301)468-5981

Pull-Thru Network
1705 Wintergreen Parkway
Normal, IL 61761
Tel: (309)262-2930

Birth Defect Research for Children, Inc.
976 Lake Baldwin Lane
Orlando, FL 32814
Tel: (407)895-0802

Genetic and Rare Diseases (GARD) Information Center
PO Box 8126
Gaithersburg, MD 20898-8126
Tel: (301)251-4925
Fax: (301)251-4911
Tel: (888)205-2311
TDD: (888)205-3223

American Association of Neurological Surgeons
5550 Meadowbrook Drive
Rolling Meadows, IL 60008-3852
Tel: (847)378-0500
Fax: (847)378-0600
Tel: (888)566-2267
Internet: and

Fetal Hope Foundation
9786 South Holland Street
Littleton, CO 80127
Tel: (303)932-0553
Tel: (877)789-4673

For a Complete Report

This is an abstract of a report from the National Organization for Rare Disorders (NORD). A copy of the complete report can be downloaded free from the NORD website for registered users. The complete report contains additional information including symptoms, causes, affected population, related disorders, standard and investigational therapies (if available), and references from medical literature. For a full-text version of this topic, go to and click on Rare Disease Database under "Rare Disease Information".

The information provided in this report is not intended for diagnostic purposes. It is provided for informational purposes only. NORD recommends that affected individuals seek the advice or counsel of their own personal physicians.

It is possible that the title of this topic is not the name you selected. Please check the Synonyms listing to find the alternate name(s) and Disorder Subdivision(s) covered by this report

This disease entry is based upon medical information available through the date at the end of the topic. Since NORD's resources are limited, it is not possible to keep every entry in the Rare Disease Database completely current and accurate. Please check with the agencies listed in the Resources section for the most current information about this disorder.

For additional information and assistance about rare disorders, please contact the National Organization for Rare Disorders at P.O. Box 1968, Danbury, CT 06813-1968; phone (203) 744-0100; web site or email

Last Updated:  9/6/2013
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