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Disease Profile

Caudal regression sequence

Prevalence estimates on Rare Medical Network websites are calculated based on data available from numerous sources, including US and European government statistics, the NIH, Orphanet, and published epidemiologic studies. Rare disease population data is recognized to be highly variable, and based on a wide variety of source data and methodologies, so the prevalence data on this site should be assumed to be estimated and cannot be considered to be absolutely correct.

1-9 / 100 000

US Estimated

Europe Estimated

Age of onset






Autosomal dominant A pathogenic variant in only one gene copy in each cell is sufficient to cause an autosomal dominant disease.


Autosomal recessive Pathogenic variants in both copies of each gene of the chromosome are needed to cause an autosomal recessive disease and observe the mutant phenotype.


dominant X-linked dominant inheritance, sometimes referred to as X-linked dominance, is a mode of genetic inheritance by which a dominant gene is carried on the X chromosome.


recessive Pathogenic variants in both copies of a gene on the X chromosome cause an X-linked recessive disorder.


Mitochondrial or multigenic Mitochondrial genetic disorders can be caused by changes (mutations) in either the mitochondrial DNA or nuclear DNA that lead to dysfunction of the mitochondria and inadequate production of energy.


Multigenic or multifactor Inheritance involving many factors, of which at least one is genetic but none is of overwhelming importance, as in the causation of a disease by multiple genetic and environmental factors.


Not applicable


Other names (AKA)

Caudal dysplasia; Sacral agenesis syndrome; Sacral regression syndrome;


Congenital and Genetic Diseases; Digestive Diseases; Kidney and Urinary Diseases;


Caudal regression sequence (CRS) affects the development of the lower (caudal) half of the body. It can impact the development of the lower back, spinal cord, and lower limbs. The kidneys, bladder, digestive tract, and genitalia may also be affected. CRS occurs during fetal development and is present at birth. The features and severity vary from person to person. In some cases, CRS is severe and can be life-threatening. In other cases, people with CRS may have problems with bowel and bladder control and be unable to walk. CRS is not known to affect the development of the brain and intelligence is generally average. The cause of CRS is unknown, and is thought to be due to a combination of genetic and environmental factors. Maternal diabetes, exposure to retinoic acid, and disorders of blood flow are thought to increase the chance for a woman to have a baby with CRS, but most babies with CRS are born to women without any known risk factor. CRS is diagnosed based on the features. Other conditions may need to be excluded before a diagnosis of CRS can be made. Treatment is focused on managing the symptoms and usually includes surgery, physical therapy, and devices to help with sitting and walking.[1][2][3][4]


The following list includes the most common signs and symptoms in people with caudal regression sequence (CRS). These features may be different from person to person. Some people may have more symptoms than others, and they can range from mild to severe. This list does not include every symptom that has been described in the condition.

Symptoms may include:[1][2][3]

  • Abnormalities of the lower spine and spinal cord
  • Underdevelopment of the legs
  • Underdeveloped hips
  • Fused kidneys or underdeveloped kidneys
  • Damage to the nerves to the bladder
  • Urethral opening on the underside of the penis (hypospadias)
  • Abnormal connection between the rectum and the vagina
  • Twisted intestine (malrotation of the large intestine)
  • Underdevelopment of the heart

People with CRS may develop curvature of the spine (scoliosis) which may sometimes affect breathing. The leg bones are often underdeveloped, and many people with CRS have difficulty with sitting and walking. Kidney abnormalities may lead to frequent urinary tract infections or kidney failure that gets worse over time. Difficulty with bladder and bowel control may occur. In some cases, the symptoms of CRS are severe and life-threatening.[3]

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

Medical Terms Other Names
Learn More:
80%-99% of people have these symptoms
Abnormal vertebral segmentation and fusion
Abnormality of the wing of the ilium
Aplasia/Hypoplasia of the sacrum
Absent/small sacrum
Absent/underdeveloped sacrum

[ more ]

Bowel incontinence
Loss of bowel control
Decreased muscle mass
Hypoplastic vertebral bodies
Underdeveloped back bones
Maternal diabetes
gestational diabetes
30%-79% of people have these symptoms
Abnormality of cardiovascular system morphology
Anal atresia
Absent anus
Ectopic kidney
Abnormal kidney location
Displaced kidney

[ more ]

Joint stiffness
Stiff joint
Stiff joints

[ more ]

Reduced tendon reflexes
Renal agenesis
Absent kidney
Missing kidney

[ more ]

Talipes equinovarus
Club feet
Club foot

[ more ]

Ureteral duplication
Double ureter
Vesicoureteral reflux
5%-29% of people have these symptoms
Ambiguous genitalia
Ambiguous external genitalia
Ambiguous external genitalia at birth
Intersex genitalia

[ more ]

Arnold-Chiari malformation
Undescended testes
Undescended testis

[ more ]

Missing ribs
Absent ribs
Decreased rib number

[ more ]

Oral cleft
Cleft of the mouth
Pulmonary hypoplasia
Small lung
Underdeveloped lung

[ more ]

Renal insufficiency
Renal failure
Renal failure in adulthood

[ more ]

Percent of people who have these symptoms is not available through HPO
Absence of the sacrum
Anterior sacral meningocele
Autosomal dominant inheritance
Back pain
Dermoid cyst
Neurogenic bladder
Lack of bladder control due to nervous system injury
Rectal abscess
Sacral lipoma
Urinary retention


The cause of caudal regression sequence (CRS) is unclear. It is thought that both genetic and environmental factors play a role in the development of CRS.

Certain conditions in pregnancy may increase the chance to have a baby with CRS. These include maternal diabetes, exposure to retinoic acid, and abnormalities in blood flow. Several genes have been identified that may also influence the chance to have a baby with CRS. In most people with CRS, the cause has not been identified.[1][3]


Making a diagnosis for a genetic or rare disease can often be challenging. Healthcare professionals typically look at a person’s medical history, symptoms, physical exam, and laboratory test results in order to make a diagnosis. The following resources provide information relating to diagnosis and testing for this condition. If you have questions about getting a diagnosis, you should contact a healthcare professional.

Testing Resources

  • The Genetic Testing Registry (GTR) provides information about the genetic tests for this condition. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.


    Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

    Organizations Supporting this Disease

      Learn more

      These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

      Where to Start

      • MedlinePlus Genetics contains information on Caudal regression sequence. This website is maintained by the National Library of Medicine.
      • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

        In-Depth Information

        • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
        • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
        • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
        • PubMed is a searchable database of medical literature and lists journal articles that discuss Caudal regression sequence. Click on the link to view a sample search on this topic.


          1. Warner T, Scullen TA, Iwanaga J, Loukas M, Bui CJ, Dumont AS, Tubbs RS. Caudal Regression Syndrome-A Review Focusing on Genetic Associations. World Neurosurg. Jun 2020; 138:461-467. https://pubmed.ncbi.nlm.nih.gov/32200015/.
          2. Kylat RI, Badr M. Caudal Regression Syndrome. Children (Basel). Nov 4, 2020; 7(11):211. https://pubmed.ncbi.nlm.nih.gov/33158301/.
          3. Kumar Y, Gupta N, Hooda K, Sharma P, Sharma S, Kochar P, Hayashi D. Caudal Regression Syndrome: A Case Series of a Rare Congenital Anomaly. Pol J Radiol. Apr 4, 2017; 82:188-192. https://pubmed.ncbi.nlm.nih.gov/28439323/.
          4. Vissarionov S, Scroder JE, Kokushin D, Murashko V, Belianchikov S, Kaplan L. Surgical Correction of Spinopelvic Instability in Children With Caudal Regression Syndrome. Global Spine J. May 2019; 9(3):260-265. https://pubmed.ncbi.nlm.nih.gov/31192092/.

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