Children's Hospital Colorado

Polycystic Kidney Disease (PKD)

What is polycystic kidney disease (PKD)?

Polycystic kidneys are kidneys that contain cysts, which are fluid-filled sacs. Cysts can range in size from small (not visible on imaging like an ultrasound) to very large (almost the size of the kidney itself). The size and number of cysts affect whether the kidney is functioning normally.

There are several types of polycystic kidney disease, most notably autosomal dominant polycystic kidney disease (ADPKD) and autosomal recessive polycystic kidney disease (ARPKD). Other types of PKD also exist, at times associated with abnormalities in other organ systems.

Kidneys with cysts are not always called polycystic kidneys. Depending on their specific appearance and other circumstances, such kidneys may also be diagnosed as multicystic dysplastic kidneys or cystic dysplastic kidneys.

What causes polycystic kidneys?

ADPKD and ARPKD are caused by genetic mutations. These mutations can be inherited, meaning there may be a family history of PKD, or they can be new genetic changes.

Genes are made from deoxyribonucleic acid (DNA), which forms a blueprint that tells our body how to form and function. Polycystic kidneys associated with other conditions can also be related to gene mutations.

When might kids develop polycystic kidneys?

Because our genes don't change substantially over our lifetime, many conditions that involve polycystic kidneys are congenital, which means they are present at birth. However, cysts take time to grow and increase in number, which means even if a child has a congenital condition that causes polycystic kidneys, they may not know it for decades.

Although less common, some injuries to previously healthy kidneys can also cause cysts.

Who gets polycystic kidneys?

Polycystic kidneys are often a symptom of a genetic disease. The genetic changes causing ADPKD and ARPKD affect all genders and ethnicities the same.