Caudal regression syndrome

Medical quality assurance by Dr. Albrecht Nonnenmacher, MD at January 4, 2017
StartDiseasesCaudal regression syndrome

Caudal regression syndrome, sometimes referred to as sacral agenesis, is a congenital disorder in which the lower half of the body fails to develop properly. This can result in significant deformities involving the lower back and limbs as well as the urinary system and gastrointestinal tract. The condition is estimated to affect approximately 1 out of every 100,000 newborns and appears to impact males and females in equal numbers. 


Definition & Facts

The long-term outlook for individuals born with caudal regression syndrome varies significantly based on the severity and type of abnormality involved. In severe cases, the cardiovascular system, kidneys, gastrointestinal tract, urinary, and respiratory systems are affected to such an extent that the child does not survive.

In the least severe cases involving a partial malformation of the sacrum, individuals may be able to ambulate relatively easily with assistive devices; however, the neuromuscular deficits often affect bowel and bladder control. The condition does not affect cognitive abilities, so those that survive infancy typically have intelligence levels within the normal range. 

Symptoms & Complaints

In individuals with caudal regression syndrome, the bones of the lower spine and the associated sections of the spinal cord are abnormally shaped or missing entirely. Those affected may have spine deformities beyond caudal regression syndrome, including scoliosis.

The abnormalities can be so severe that they affect the shape of the chest and interfere with breathing. In some cases, the membranes that protect and cover the spinal cord or even the spinal cord itself may protrude through the spinal canal. The hip bones are often underdeveloped and have a limited range of motion. The bones of the leg may be underdeveloped and bent in a frog-like position with the feet tucked under the hips with the knees pointing outward.

The buttocks may be flat or dimpled, and the anus may be obstructed or malformed. Club feet and other foot anomalies are common as well as decreased sensation affecting the lower limbs. A wide range of genitourinary and gastrointestinal malformations affecting the kidneys, bladder, genitals, and intestines can occur with caudal regression syndrome. This can lead to a loss of bowel and bladder function, constipation and urinary tract infections, and a progressive loss of kidney function. Congenital heart defects are also associated with caudal regression syndrome.


Although the exact cause of caudal regression syndrome is not clear, there is some evidence suggesting that it may be caused by a variety of genetic factors and environmental factors. The majority of cases cannot be attributed to one specific cause. It is known that caudal regression syndrome occurs more often in children of women with diabetes.

Although the reason for the connection is not fully understood, maternal diabetes is believed to be a factor in approximately 16 percent of cases of caudal regression syndrome. Environmental factors, including alcohol, amino acid imbalances, and a lack of oxygen may also contribute to the development of the condition.

Genetic mutations involving the VANGL1 gene have been identified in some individuals with caudal regression syndrome; however, the exact nature of the association is still not fully understood. The VANGL1 gene is located on chromosome 1. The mutation is autosomal dominant, which means that the affected individual only has to inherit the defective gene from one parent in order to have the condition.

It is believed that these environmental or genetic factors affect the development of the embryonic tissue or somehow alter the blood flow to the developing fetus around day 28 of the pregnancy, which impairs the formation of the lower part of the body. 

Diagnosis & Tests

Caudal regression syndrome can often be diagnosed prenatally. An ultrasound, which uses high-frequency sound waves to create an image of the unborn child, will typically show a lack of lower limb development and possible defects with other body systems. After birth, an echocardiogram, which is an ultrasound of the heart, may be used to determine if and to what extent the heart may be involved.

Magnetic resonance imaging, also known as an MRI, may be used to assess the extent of spinal defects. MRIs use radio waves and powerful magnets to create cross-sectional images of body tissues and organs. 

Treatment & Therapy

The treatments and therapies for caudal regression syndrome are directed to the individual’s specific symptoms. Most patients with the condition require treatment from a coordinated team of specialists, including neurologists, urologists, neurosurgeons, pediatricians, cardiologists, nephrologists, and others.

Children with symptoms on the severe end of the spectrum may require extensive medical care and surgical intervention. It is not unusual for individuals with the condition to undergo multiple surgeries to address spinal, heart, urogenital, orthopedic, and intestinal deformities. Issues with bowel and bladder function may require a colostomy, self catheterization, and other measures. Renal complications, including frequent urinary tract infections and progressive kidney dysfunction, may require medications or various medical procedures.

Depending on the extent of the lower limb abnormality, physical therapy and occupational therapy may help improve strength and function. Assistive devices, including crutches, walkers, and wheelchairs, may help some individuals with caudal regression syndrome perform activities of daily living and achieve a higher level of independence. 

Prevention & Prophylaxis

Since the underlying cause of caudal regression syndrome is unknown in the majority of cases, there is little that can be done to prevent it other than seeking proper prenatal care.

Pregnant women should avoid substances known to harm fetal development, including alcohol, chemicals, illicit drugs, and medications not approved by a doctor. Since there appears to be a connection between caudal regression syndrome and maternal diabetes, women with diabetes should work closely with their doctor to control blood sugar levels during pregnancy.

Individuals with the condition should receive ongoing follow-up care for urologic issues that can result in decreased renal function. It is important that children with the condition receive early intervention to help them achieve their highest potential and enjoy the best possible quality of life. This includes physical therapy as well as psychological, medical, vocational, and social services.

Even with the physical limitations associated with the condition, adults with caudal regression syndrome are often able to live and function independently.