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Caudal Regression Syndrome (Sacral Agenesis)

What Is Caudal Regression Syndrome?

Caudal regression syndrome is an extremely rare condition. It affects how the lower part of the body develops in the womb. From an orthopaedic and spine standpoint, it is diagnosed as sacral agenesis. Sacral agenesis occurs when the sacrum, the lowest part of the spine, doesn’t form normally or at all.

The condition can vary widely from patient to patient. It can affect a child’s:

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

Caudal regression syndrome affects males and females in equal numbers. The incidence of the disorder is estimated to be one to two out of every 100,000 live births.

Caudal Regression Syndrome Causes

The exact cause of caudal regression syndrome is unknown. Researchers believe that both environmental and genetic factors may play a role in its development.

Some children with congenital caudal regression syndrome may have a genetic predisposition for the disorder.

The environmental factors that may lead to fetal caudal regression syndrome are unknown. Potential factors include lack of oxygen, amino acid imbalances, or exposure to organic solvents while in the womb. More research is needed to determine which of these may play a role.

Caudal regression syndrome occurs more often in babies carried by women with diabetes than in those without diabetes. However, not every child who has the condition is born to a diabetic mother. The reason women with diabetes are at greater risk for having a child with this condition isn’t fully understood.

Caudal Regression Syndrome Symptoms

Pediatric caudal regression syndrome affects the lower half of the body. Symptoms can range from mild to severe.

The condition can affect the development and function of the digestive tract, kidneys and urinary tract. Symptoms may include:

  • Bladder nerves don’t send signals to the brain, causing the bladder to function abnormally
  • Bladder comes out of an opening in the abdominal wall
  • More tubes than necessary take urine from the kidneys to the bladder
  • Lack of bladder or bowel control
  • Frequent urinary tract infections
  • Constipation
  • Blocked anal opening
  • Missing kidney, abnormally shaped kidneys or kidneys that join together, which can cause kidney failure

Caudal regression syndrome can also affect the development and function of reproductive organs. Symptoms may include:

  • Undeveloped reproductive organs
  • Undescended testes
  • Opening of the urethra is on the underside of the penis
  • Connection between the lower part of the large intestine (rectum) and the vagina causes bowel contents to leak out and pass through the vagina

Caudal regression syndrome also can affect other internal organs, including the:

  • Heart.
  • Large intestine.

Caudal regression syndrome can affect how bones develop. Symptoms may include:

  • Breathing problems caused by an irregularly shaped chest.
  • Scoliosis, or curvature of the spine.
  • Small hip bones.
  • Flat, dimpled buttocks.
  • Vertebrae don’t completely close around the spinal cord, causing a fluid-filled sac to form.
  • Abnormally shaped or missing bones in the spinal cord and lower spine.
  • Less feeling in the lower half of the body.

Caudal regression syndrome varies from patient to patient. Children with underdeveloped bones in their legs from sacral agenesis may stand differently. This can affect how they walk. Symptoms may include:

  • Calcaneovalgus (feet turn out and up)
  • Clubfeet (feet turn inward)
  • Frog-leg position (legs bend with knees pointed out and feet in line with hips)

Caudal Regression Syndrome Diagnosis

Caudal regression syndrome may be diagnosed before birth by doing a prenatal ultrasound.

Once a child is born, doctors can use additional tests, including an X-ray or magnetic resonance imaging (MRI), to further examine the effects of caudal regression syndrome on a child’s anatomy.

Caudal Regression Syndrome Treatment

Treatment for caudal regression syndrome involves more than one medical team. The type of treatment, and the specialists involved, will depend on the severity of the condition and the symptoms a child is having.

The healthcare team for caudal regression syndrome may include:

  • Bone specialists (orthopedists).
  • Brain, spinal cord and nerve specialists (neurologists).
  • Child health specialists (pediatricians).
  • Heart specialists (cardiologists).
  • Kidney specialists (nephrologists).
  • Urinary tract specialists (urologists).

Treatment for caudal regression syndrome may include:

  • Medications to treat symptoms.
  • Prosthetics.
  • Assisted mobility devices.
  • Braces.
  • A ventilator to help with breathing.
  • Surgery to repair symptoms that affect the skeletal system.
  • Surgery to improve the function of a child’s bowels, genitals, organs or urinary tract.

A child with caudal regression syndrome may need more than one surgery to manage symptoms as the child grows. Treatment with medications or surgery may begin soon after a child is born.

Caudal regression syndrome can affect your child’s ability to pee and poop. Treatment options may include:

  • Surgery to repair urinary tract or bowel blockages.
  • Inserting a catheter to remove pee from the body.
  • Creating a surgical opening (colostomy) in the abdominal wall to allow poop to bypass the colon and exit the body in an external bag

Caudal Regression Syndrome Prognosis

There is no cure for caudal regression syndrome. It’s a lifelong condition, but children can live healthy lives. Surgeries can help correct abnormalities that occurred during a child’s development. Treatments by various specialists can help manage symptoms throughout a child’s life.

Last Updated 01/2023

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Who treats this?

The Division of Urology treats a complete range of disorders affecting the urinary and genital tracts, from common concerns to rare and complex abnormalities.

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