Polycystic Kidney Disease in Children

ADPKD is the most common form of polycystic kidney disease, affecting about 600,000 people in the United States and accounting for more than 98 percent of all PKD cases. Autosomal dominant means that if one parent has the disease, every pregnancy carries a 50 percent chance that the disease-gene will pass to the child. Both males and females are equally affected. 
 
There are two different groups of children with ADPKD:

• Those diagnosed before birth or in their first year of life with large cystic kidneys
• Those diagnosed in childhood 

Children diagnosed in the first year of life:

• Most are diagnosed in utero with large kidney cysts. Most develop high blood pressure (hypertension) and loss of kidney function in childhood, which should be monitored and treated by a pediatric nephrologist. 
• Some of these children may develop kidney failure by their teenage years.

Children diagnosed after the first year of life:

• For many of these children, ADPKD is an “incidental” diagnosis made by an ultrasound or other imaging study performed for another clinical problem.
• These children may develop hypertension as well as other signs and symptoms of ADPKD. They should be monitored by a primary care physician or a pediatric nephrologist.
• Almost all children who are diagnosed after the first year of life will have normal kidney function throughout childhood.

Autosomal recessive PKD is a rarer form of polycystic kidney disease caused by a different gene than those involved in ADPKD. Recent estimates suggest that there are 1,500 ARPKD patients in the U.S. 

Autosomal recessive means that both parents carry an abnormal copy of the gene, but they do not have clinical signs and symptoms. A baby who inherits an abnormal copy of the disease-gene from each parent will have ARPKD. For these parents, there is a 25 percent risk for every pregnancy that the child will have ARPKD. Both males and females are equally affected. 

Typically, children with ARPKD are identified by ultrasound before birth (prenatal) or shortly after birth. 

Major issues for ARPKD infants and children:

• Newborn period. While ARPKD is a serious condition for newborns, about 80 percent of ARPKD children survive the newborn period and these children typically survive well into adulthood.
• Kidneys. Hypertension can be a major issue for ARPKD patients, requiring expert management by a pediatric nephrologist. Loss of kidney function can occur as the child ages, requiring dialysis or kidney transplantation. With advances in clinical care over the past 20 years, more than 60-70 percent of ARPKD children can maintain kidney function throughout childhood.
• Liver. The liver cysts in ARPKD can cause scarring (fibrosis) in the liver, which can lead to increased pressure in the blood vessels of the liver (portal hypertension), causing blood flow to back up into vessels that surround the esophagus, stomach and intestines. Children with ARPKD who develop portal hypertension have increased risk of bleeding from these swollen blood vessels (varices), as well as an increased risk of infection in the liver cysts (cholangitis). They should be monitored and treated by a pediatric hepatologist. Liver function remains relatively normally in these children and the need for liver transplantation is rare.