What is polycystic kidney disease (PKD)?
Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts filled with fluid in the kidneys. PKD cysts can reduce kidney function, leading to kidney failure. People with PKD can also have cysts in the liver and problems in other organs, such as the heart and blood vessels in the brain.
PKD is the fourth leading cause of kidney failure and affects approximately 600,000 people in the U.S., according to the National Kidney Foundation (NKF). The NKF states that about 50 percent of people with autosomal dominant form of PKD progress to kidney failure by age 60, and about 60 percent will have kidney failure by age 70.
What are the different types of PKD?
There are two primary inherited forms of PKD and one non-inherited form:
Autosomal dominant PKD (inherited)
This is the most common inherited form of polycystic kidney disease, accounting for about 90 percent of all PKD cases. "Autosomal dominant" means that if one parent has the disease, there is a 50 percent chance that the disease will pass to a child, and that both males and females are equally affected. These cases usually are diagnosed in adulthood.
Usually, at least one parent must have the disease for a child to inherit it. In 10 percent of cases, there may be no family history of PKD. These cases are new mutations in a family. In very few cases, autosomal dominant PKD occurs spontaneously after conception. Parents would not be at increased risk to have additional children with PKD. But individuals with PKD have a 50/50 chance of passing the gene on to their children.
Autosomal dominant PKD is often called the adult polycystic kidney disease. Symptoms usually develop between age 30 and 40 (but they can begin as early as childhood), and may include the following:
Detectable abdominal mass
Pale color to skin
High blood pressure
Aneurysms (bulging of the walls of blood vessels) in the brain
Diverticulosis (pouches in the intestines)
Urinary tract infections
Hematuria (blood in the urine)
Liver and pancreatic cysts
Abnormal heart valves
Autosomal dominant PKD may occur with other conditions including:
Tuberous sclerosis (a genetic syndrome involving seizures, mental retardation, benign tumors, and skin lesions)
Severe eye problems
The symptoms of autosomal dominant PKD may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
Diagnosis of autosomal dominant PKD may include the use of imaging techniques to detect cysts on the kidney and other organs and a review of the family history of autosomal dominant PKD. There are three different dominant genes which have been identified that further subdivide autosomal dominant PKD into PKD1, PKD2, and PKD3.
A physician will establish a treatment protocol for autosomal dominant PKD only after careful consideration of the child's symptoms and medical history. Treatment may include:
Surgery to shrink cysts and relieve pain
Treatment for high blood pressure
Treatment for urinary tract infections
Autosomal recessive PKD (inherited)
Autosomal recessive PKD is a rare, inherited form of polycystic kidney disease thought to be caused by a particular genetic flaw that is different from the genetic flaw that causes autosomal dominant PKD. Parents who do not have the disease can have a child with the disease if both parents carry the abnormal gene and both pass the gene to their child. Carrier parents have a 25 percent chance with each pregnancy to have a child with this type of PKD. Males and females are equally affected. Autosomal recessive PKD is sometimes detected prenatally (before birth) using a fetal ultrasound.
Symptoms of autosomal recessive PKD can begin before birth. In most cases, the earlier the onset, the more severe the outcome. There are four different types of autosomal recessive PKD, depending upon the child's age when symptoms become evident:
Perinatal form (present at birth)
Neonatal form (presents within the first month of life)
Infantile form (presents between age 3 months and 6 months)
Juvenile form (presents after age 1)
Children born with autosomal recessive PKD may develop kidney failure within a few years and often experience the following:
High blood pressure
Urinary tract infections
The disease also usually affects the liver, spleen, and pancreas, resulting in low blood cell counts, varicose veins, and hemorrhoids.
The symptoms of autosomal recessive PKD may resemble other conditions or medical problems. Always consult your child's physician for a diagnosis.
Diagnosis often includes ultrasound imaging of the fetus or newborn to reveal cysts in the kidneys. Ultrasound examination of kidneys of relatives may also be helpful.
Your child's physician will establish a treatment protocol for autosomal recessive PKD only after careful consideration of the child's symptoms and medical profile. Treatment may include:
Acquired cystic kidney disease, or ACKD (non-inherited)
Acquired cystic kidney disease (ACKD) may develop in association with long-term kidney problems, especially in people who have kidney failure and who have been on dialysis for a long time. Therefore, it tends to occur later in life and is an acquired, not inherited, form of PKD. Often there are cysts in other organs, such as the liver and the pancreas.