Autosomal Dominant Polycystic Kidney Disease

Polycystic Kidneys

Autosomal Dominant Polycystic Kidney Disease: An Overview

Polycystic kidney disease (PKD) is a genetic condition characterized by the growth of numerous cysts in the kidneys. These cysts are filled with fluid. Polycystic kidney disease cysts can slowly replace much of the mass of the kidneys, reducing kidney function and leading to kidney failure.

Autosomal dominant polycystic kidney disease is one type of polycystic kidney disease and is one of the most common inherited conditions. An inherited condition is one that is passed from parent to child through a defect (mutation) in a gene.

Many people with autosomal dominant polycystic kidney disease live for decades without developing polycystic kidney disease symptoms. For this reason, autosomal dominant polycystic kidney disease is often called "adult polycystic kidney disease." Yet, in some cases, cysts may form earlier, even in the first years of life.

Understanding the Kidneys and Polycystic Kidney Disease

The kidneys are two organs, each about the size of a fist, located toward the back of a person's upper abdomen. The kidneys filter wastes from the blood to form urine. They also regulate amounts of certain vital substances in the body.

In a person with autosomal dominant polycystic kidney disease, clusters of fluid-filled sacs (cysts) develop in the kidneys. The cysts grow out of nephrons, the tiny filtering units inside the kidneys. Eventually, the cysts separate from the nephrons and continue to enlarge. The kidneys enlarge along with the cysts (which can number in the thousands), while roughly retaining their kidney shape. In a person with fully-developed polycystic kidney disease, a cyst-filled kidney can weigh as much as 22 pounds. Symptoms of polycystic kidney disease occur because of these cysts and the damage they cause. Cysts may also develop in other organs, particularly the liver, spleen, and pancreas.

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