Single Gene Inheritance: Polycystic Kidney Disease

One of the most common genetic and life threatening diseases is one with which you might not be familiar. This disease affects more than 600,000 Americans and 12.5 million people worldwide, making no distinction among gender, ethnicity, or age and is the fourth leading cause of kidney failure.

This condition is called polycystic kidney disease (PKD) and is an inherited disorder, either autosomal dominant or recessive in form. The dominant form, ADPKD, is the most common and involves a mutation in the PKD1 gene on chromosome 16 and affects 1 in 400-500 adults. The recessive form, ARPKD, affects young children with an incidence of 1 in 10,000 and is due to a change in the PKD2 gene on chromosome 4.

The kidneys are a regulating system, maintaining electrolyte balances in the body, filtering blood and plasma, and producing certain hormones. Normal kidneys are about 5-6 inches in length but in this disease, the presence of multiple cysts enlarges the kidneys and impairs normal functioning. Early in the disease there are no symptoms. Typically the first sign is high blood pressure, affecting 60-70% of those with ADPKD. Chronic pain, blood in the urine, urinary tract infections, and kidney stones are additional symptoms that may occur.

Because PKD is an inherited disease, the dominant form is passed through family generations. Each child of a parent with ADPKD has a 50% chance of inheriting the disease. Currently there is no known treatment or cure other than dialysis and kidney transplant. Affected individuals can make and practice personal healthcare choices to control development of the disease, including eating a low protein diet, avoiding excessive salt intake, and drinking lots of water.

For more information on PKD you can visit the PKD foundation site at www.pkdcure.org.