What Is Bilateral Renal Agenesis?

Bilateral renal agenesis is a congenital condition in which the kidneys fail to develop. Typically, this condition is not compatible with life after birth since the kidneys play a critical role in maintaining the health of the body. Although the exact cause of bilateral renal agenesis is unknown, babies with the syndrome develop abnormalities such as poor lung development and characteristic facial features. There is no good treatment for bilateral renal agenesis, and most newborns with the condition do not live for more than a few months.

Many researchers have attempted to understand why bilateral renal agenesis occurs. Some think that it is caused by an early event that disrupts the development of the embryonic precursors of the kidneys. Problems such as genetic defects, exposure to cocaine, and maternal ingestion of the medication retinoic acid have all been implicated as possible risk factors for the development of bilateral renal agenesis. In many cases, however, the reason why a baby fails to develop kidneys is unknown.

Developing babies who have bilateral renal agenesis typically have other characteristic abnormalities because they go through the so-called Potter Sequence of development. Without the kidneys present to produce urine, the fetus has a decreased amount of amniotic fluid present in the womb, a condition referred to as oligohydramnios. This fluid usually serves as a cushion, protecting the fetus from harm and giving it sufficient space to grow and develop. A lack of fluid results in poor lung development, since breathing in sufficient quantities of amniotic fluid is important for lung maturation. Developing babies also typically develop a flattened face with wide-set eyes and low ears due to this lack of fluid.

The diagnosis of bilateral renal agenesis can often be made while the fetus is still in the womb. Routine ultrasounds check the size of the baby and the amount of amniotic fluid that surrounds it. If low quantities of amniotic fluid are present, the baby is diagnosed with oligohydramnios and more sophisticated tests are performed to understand why low amniotic fluid volumes are present.

Although prior to birth a baby with bilateral renal agenesis can survive because of the mother’s kidney function, death generally occurs within weeks to months after birth. Sometimes dialysis, a procedure that replaces some functions of the kidney, can be performed on these newborns. Often, however, too many other congenital abnormalities are present and the babies do not survive.