Children's Hospital Colorado

Dysplastic Kidneys

What are dysplastic kidneys?

Dysplastic kidneys (also known as kidney dysplasia) are kidneys that did not develop properly during pregnancy. The kidneys may be a different size and shape than average kidneys and they often also have fluid-filled sacs called cysts. The cysts prevent the kidney from working normally. Dysplastic kidneys can have various degrees of function, ranging from mildly to severely decreased function, which requires medical treatment. A multicystic dysplastic kidney (MCDK) is a type of dysplastic kidney that has no or minimal function and is often covered in cysts.

Your child may have one dysplastic kidney, with the other one being healthy, or they can have two dysplastic kidneys. When both kidneys are affected, there is a higher risk of kidney disease because there is no healthy kidney to "make up" for the dysplastic kidney.

What causes dysplastic kidneys?

In developing babies, kidney development happens in a series of stages. Occasionally, this process is altered or disrupted by unnoticed and unexplained events that cause a dysplastic kidney. These events can sometimes be linked to an altered gene that is passed down from one parent. One recognized cause of dysplastic kidneys is the use of certain blood pressure medications during pregnancy.

Dysplastic kidneys can occur in a child as a single condition, or they can be part of a larger condition that also affects other organs. Congenital abnormalities of the kidneys and the urinary tract or CAKUT, are a group of conditions often associated with dysplastic kidneys in addition to an abnormally developed lower urinary tract. In other cases, dysplastic kidneys can be found in combination with malformations that affect both the urinary tract and other organ systems such as the genitalia, the heart or the lower digestive tract.

Who gets dysplastic kidneys?

Most often, the development of dysplastic kidneys is a random event that can occur across all genders and ethnicities and is not tied to events that occurred during pregnancy. Dysplastic kidneys can also be part of malformation syndromes that have specific underlying genetic defects called mutations.