Renal Agenesis: Symptoms, Risk Factors, Causes, Diagnosis, Treatment and Prevention

It is a condition in which a newborn is missing one or both kidneys.

Unilateral Renal Agenesis (ARU) is the absence of a kidney. The renal agenesis Bilateral (ARB) is the absence of both kidneys.

According to the March of Dimes, both types of renal agenesis occur in less than 1 percent of annual births. Less than 1 in every 1,000 newborns has unilateral renal agenesis.

Bilateral renal agenesis is much less frequent, occurring in approximately 1 in 3,000 births. The kidneys perform functions that are necessary for life. In healthy people, the kidneys:

  • They produce urine, which removes urea or liquid waste from the blood.
  • They maintain a balance of sodium, potassium, and other electrolytes in the blood.
  • They supplement the hormone erythropoietin, helping the growth of red blood cells.
  • They produce the hormone renin to help regulate blood pressure.
  • They produce calcitriol, also known as vitamin D, which helps the body absorb calcium and phosphate from the gastrointestinal tract.

Everyone needs at least part of a kidney to survive. Without either kidney, the body can not eliminate waste or water properly.

This accumulation of waste and fluids can compensate for the balance of essential chemicals in the blood and leads to death without treatment.

What are the signs and symptoms of renal agenesis?

Both types of renal agenesis are associated with other congenital disabilities, such as problems with:


  • Genitals and urinary tract.
  • Stomach and intestines.
  • Heart.
  • Muscles and bones.
  • Eyes and ears

Babies born with unilateral renal agenesis may have signs and symptoms at birth, in childhood, or later. Symptoms may include:

  • High blood pressure
  • Kidney with malfunction.
  • Urine with protein or blood.
  • Swelling in the face, hands, or legs.

Babies born with bilateral renal agenesis are very sick and usually do not survive. In general, they have different physical characteristics that include:

  • Widely separated eyes with folds of skin over eyelids.
  • Ears that get low.
  • A nose that is pressed flat and wide.
  • A small chin
  • Defects of arms and legs.

This group of defects is known as Potter syndrome. It occurs due to the production of reduced or absent urine from the fetal kidneys.

Urine is a large part of the amniotic fluid surrounding and protecting the fetus.

Risk factor’s

Who is at risk for renal agenesis?

The risk factors for renal agenesis in newborns seem to be multifactorial. Genetic, environmental, and lifestyle factors create a person’s risk.

For example, some preliminary studies have linked maternal diabetes, the mother’s young age, and alcohol consumption during pregnancy with renal agenesis.

Studies have shown that pre-gestational obesity, alcohol consumption, and smoking are related to renal agenesis.

Drinking excessively, or taking more than four drinks for 2 hours during the second month of pregnancy, increases the risk.

Environmental factors can also cause kidney defects, such as renal agenesis. For example, maternal drugs, illegal drugs, or exposure to toxins or poisons during pregnancy may be factors.


Both Unilateral Renal Agenesis and Bilateral Renal Agenesis occur when the ureic outbreak, also called kidney outbreak, does not develop early in fetal growth.

The exact cause of renal agenesis in newborns is not known. Most cases of renal agenesis are not inherited from the parents, nor are they the result of any mother’s behavior.

Some cases, however, are caused by genetic mutations. These mutations are transmitted from parents who have the disorder or are carriers of the mutated gene.

Prenatal tests can often help determine if these mutations are present.

Diagnosis of renal agenesis

Renal agenesis is typically found during routine prenatal ultrasounds. If your doctor identifies ARB in your child, you can use a prenatal MRI to confirm the absence of both kidneys.

Treatment and perspectives

Most newborns with Unilateral Renal Agenesis have few limitations and usually live. The prognosis depends on the health of the remaining kidney and the presence of other abnormalities.

To avoid injuring the remaining kidney, you may need to avoid contact sports when they are older.

Once diagnosed, patients of any age with Unilateral Renal Agenesis should undergo annual blood pressure and urine and blood tests to monitor kidney function.

Bilateral Renal Agenesis is typically fatal in the first days of a newborn’s life. Newborns usually die from underdeveloped lungs shortly after birth.

However, some newborns with Bilateral Renal Agenesis survive. They must undergo long-term dialysis to do the work of their missing kidneys.

Dialysis is a treatment that filters and purifies the blood using a machine. This helps maintain the balance of the body when the kidneys can not do their job.

Factors such as lung development and general health determine the success of this treatment.

The goal is to keep these babies alive with dialysis and other treatments until they grow strong enough to undergo a kidney transplant.


Prevention is not possible since the exact cause of Unilateral Renal Agenesis and Bilateral Renal Agenesis is unknown. Genetic factors can not be changed.

Antenatal counseling can help prospective parents understand the risks of having a baby with renal agenesis.

Women can reduce the risk of renal agenesis by lowering exposure to possible environmental factors before and during pregnancy.

These include the use of alcohol and certain medications that can affect the development of the kidney.


The cause of renal agenesis is not known. This congenital disability is sometimes caused by mutated genes that pass from the parents to the baby. Consider prenatal genetic testing to determine your baby’s risk if you have a family history of renal agenesis.

With medical care and treatment, babies born with a kidney usually survive and live relatively everyday life. Those born without kidneys typically do not survive. Those who survive will need long-term dialysis.