Caudal Regression Syndrome

Caudal regression syndrome is a condition that affects how the fetus develops in the uterus. This condition targets your child’s bones, renal system and gastrointestinal tract. Children diagnosed with this condition may have trouble peeing and pooping. Treatment is symptomatic and usually involves surgery.


An illustration of a baby with caudal regression syndrome and a magnified image of their spine.
Caudal regression syndrome can affect the shape of your baby’s chest, hips, legs and spine.

What is caudal regression syndrome?

Caudal regression syndrome (CRS) is a condition that affects how the fetus develops in the uterus. This condition can affect the:

  • Lower back.
  • Legs.
  • Urinary tract.
  • Gastrointestinal tract.
  • Genitals.

Infants diagnosed with this condition might experience challenges walking, pooping and peeing.


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Who does caudal regression syndrome affect?

Caudal regression syndrome can affect anyone. Some causes are genetic, and the genetic mutation usually happens sporadically. This means CRS typically occurs even if you don’t have a history of the condition in your biological family.

How common is caudal regression syndrome?

Caudal regression syndrome affects an estimated 1 to 2 out of every 100,000 newborns worldwide. CRS is more common among infants born to parents who have diabetes, where it affects an estimated 1 in 350 newborns.


Symptoms and Causes

What are the symptoms of caudal regression syndrome?

Symptoms of caudal regression syndrome affect the lower half of your child’s body and range from mild to severe. Your child could experience a few symptoms or several symptoms depending on the severity of their diagnosis.

Skeletal system symptoms

Symptoms of caudal regression syndrome can affect how your child’s bones develop, including:

  • Bones of their spinal cord and lower spine (vertebrae) have an abnormal shape or are missing.
  • A fluid-filled sac forms near their spinal cord where their vertebrae didn’t completely close around their spinal cord.
  • Curvature of their spine (scoliosis).
  • Small hip bones.
  • Irregularly shaped chest, which causes breathing problems.
  • Flat and dimpled buttocks.
  • Minimal feeling in the lower half of their body.

Infants with underdeveloped bones in their legs caused by caudal regression syndrome may have an irregular stance that can affect how they walk. This could include:

  • Frog-leg position: Your child’s legs bend with their knees pointed outward and their feet in line with their hips.
  • Clubfeet: Your child’s feet turn inward.
  • Calcaneovalgus: Your child’s feet turn outward and upward.

Organ symptoms

Symptoms of caudal regression syndrome can affect the development and function of your child’s renal system, digestive and urinary tract. Symptoms could include:

  • Abnormally shaped kidneys, a missing kidney or the kidneys fuse together. This can cause kidney failure.
  • More tubes than necessary take urine from their kidneys to their bladder (ureteral duplication).
  • Frequent urinary tract infections.
  • Their bladder comes out of an opening in their abdominal wall (bladder exstrophy).
  • Bladder nerves that control the function of their bladder don’t send signals to their brain to work as expected (neurogenic bladder).
  • Lack of bladder or bowel control.
  • Constipation.
  • Blocked anal opening (imperforate anus).

Caudal regression syndrome can also affect the development and function of your child’s reproductive organs. Symptoms that affect their reproductive organs include:

  • The opening of their urethra is on the underside of their penis (hypospadias).
  • Their testes don’t descend (cryptorchidism).
  • The connection between the lower part of their large intestine (rectum) and their vagina causes bowel contents to leak out and pass through their vagina (rectovaginal fistula).
  • Reproductive organs didn’t develop (genital agenesis).

Symptoms of caudal regression syndrome can also affect other internal organs in your child’s body, including:

What causes caudal regression syndrome?

Multiple genetic and environmental factors can cause caudal regression syndrome in a newborn including:

  • Diabetes: The birthing parent has a diabetes diagnosis. Changes to the parent’s blood glucose levels and metabolism can affect fetal development.
  • Mesoderm: The mesoderm is the middle layer of tissue in a developing embryo that consists of a group of cells that are responsible for building structural parts (bones and organs) of a fetus’ body. Around day 28 of pregnancy, genetic changes can affect the development of the mesoderm.
  • Abdominal artery abnormality: An artery is a tube responsible for sending blood to different parts of your body. For a developing fetus, the artery that brings blood to the lower part of their body is facing a direction other than toward the lower part of their body, which prevents blood from reaching that area.
  • Genetic mutation: Changes to your genes that occur during conception (when the egg and sperm meet) can cause this condition, specifically genetic mutations in the HLXB9 or the VANGL1

Some cases of caudal regression syndrome happen sporadically, or randomly, where a cause isn’t clear. Research is ongoing to learn more about the possible causes of this condition and how it affects newborns.


Diagnosis and Tests

How is caudal regression syndrome diagnosed?

Your healthcare provider can sometimes diagnose caudal regression syndrome before your child is born during a prenatal ultrasound. During this test, they’ll look for symptoms of the condition that affect the development of the lower half of your child’s body.

Once your child is born, your provider might offer additional tests to learn more about the extent of their diagnosis. Tests could include an imaging test, like an X-ray or an MRI, to examine the effects of the condition on your child’s bones and organs.

Management and Treatment

How is caudal regression syndrome treated?

Treatment for caudal regression syndrome is symptomatic and unique to each child diagnosed with the condition and could include:

  • Surgery to repair skeletal system symptoms or symptoms that affect your child’s bones.
  • Surgery to improve the function of your child’s genitals, organs, urinary tract and/or bowels.
  • Medications to reduce symptoms.
  • Using a ventilator to help with breathing.
  • Wearing a brace, using prosthetics or assisted mobility devices to help your child move.

Your child may need more than one surgery to manage their symptoms as they grow. Based on your child’s symptoms, they might need to start treatment with medications or surgery soon after they’re born or during early infancy.

How do you pee or poop with caudal regression syndrome?

Caudal regression syndrome can affect your child’s ability to pee and poop. If your child receives a CRS diagnosis, they may need help going to the bathroom. Your child’s healthcare provider will offer possible treatment options to help your child by:

  • Inserting a catheter to remove urine from their body.
  • Repairing any urinary tract or bowel blockages with surgery.
  • Diverting their stool via a surgical opening (colostomy) in your child’s abdominal wall (stoma). This allows the stool to bypass your child’s colon and exit their body in an external bag.

Your child’s bowels might not be able to function as expected throughout their life. This can be a challenging situation to navigate. Your child’s healthcare team will create a treatment plan to help you and your child manage, adapt and adjust to their condition to improve your child’s quality of life.

Who treats caudal regression syndrome?

Your child will receive care from a variety of specialists who are experts in specific areas of your child’s body. Their healthcare team could include:


How can I prevent caudal regression syndrome?

You can’t prevent caudal regression syndrome because some of the causes are the result of random genetic changes that you can’t predict or prevent. You can take steps to reduce your risk of having a child with caudal regression syndrome by working with your healthcare provider to manage your blood glucose levels if you have diabetes during pregnancy.

Outlook / Prognosis

What can I expect if I have a child diagnosed with caudal regression syndrome?

Caudal regression syndrome is a lifelong condition without a cure. Symptoms affect several different parts of your child’s body and require a team of specialists to treat and manage the condition throughout your child’s life. Your child may need surgery early during infancy to improve any growth abnormalities that occurred during their development. Your child may spend a few weeks in the hospital after they’re born to make sure they’re healthy. Your healthcare team will work with you and your child’s caretakers to help you learn more about your child’s diagnosis, what symptoms you should monitor at home and how you can help your baby grow and thrive.

Living With

When should I see my child’s healthcare provider?

Visit your child’s healthcare provider if:

  • Their surgical site isn’t healing, swells or leaks fluid or pus.
  • They aren’t able to reach growth or developmental milestones for their age.
  • They’re eating but not having any bowel movements.
  • They experience pain or discomfort when going to the bathroom.

Visit the emergency room if your child has trouble breathing or if their heart beats irregularly, or for any other concerning symptoms.

What questions should I ask my doctor?

  • How can my child go to the bathroom with caudal regression syndrome?
  • What symptoms should I look out for?
  • Should my child eat a special diet?
  • What should I do if my child isn’t able to go to the bathroom?

A note from Cleveland Clinic

Learning that your child has a caudal regression syndrome diagnosis can be challenging and overwhelming. Your child may have difficulty with mobility and using the toilet. Their symptoms could require several surgeries to repair parts of their body that didn’t develop in the uterus. Adapting these changes can be difficult. Some families find comfort by joining support groups or speaking with a mental health professional. Your child’s healthcare team will work closely with you to make sure you understand what’s happening with your child so you can help them grow.

Medically Reviewed

Last reviewed on 07/01/2022.

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