Autosomal dominant polycystic kidney disease (ADPKD) is the most common genetic or inherited disease of the kidney, characterized by the growth of numerous cysts in the kidneys. Polycystic kidney disease (PKD) is the fourth leading cause of chronic kidney disease. In PKD, other organs in which cysts can be seen are the liver, brain, intestines, pancreas, ovaries and spleen.
What is the incidence of PKD?
The incidence of autosomal dominant PKD is the same in all races, occurs equally in males and females and affects about 1 in 1,000 people worldwide. About 5% of all chronic kidney disease patients requiring dialysis or kidney transplantation have PKD.
How is the kidney affected in PKD?
In autosomal dominant PKD multiple clusters of cysts (fluid-filled sacs) are seen in both kidneys.
Sizes of cysts in PKD are variable (diameter ranging from a pinhead to as large 10 cm. or more). With time cysts increase in size and slowly compress and damage healthy kidney tissue.
Such damage leads to hypertension, loss of protein in urine and reduction in kidney function, causing chronic kidney failure.
In a long period (after years) chronic kidney failure worsens and leads to severe kidney failure (endstage kidney disease), ultimately requiring dialysis or kidney transplantation.
Symptoms of PKD
Many people with autosomal dominant PKD live for several decades without developing symptoms. Most patients with PKD develop symptoms after the age of 30 to 40 years. Common symptoms of PKD are:
Does everyone with PKD develop kidney failure?
No. Kidney failure does not occur in all patients with PKD. About 50 % of patients with PKD will have kidney failure by the age of 60, and about 60 % will have kidney failure by the age of 70. The risk factors for progression of CKD in patients with PKD include: larger renal size, younger age at diagnosis, hypertension (particularly before age 35 years), proteinuria (> 300 mgs/day), gross hematuria, male gender, > 3 pregnancies, certain genetic mutations (PKD1 gene mutation), as well as tobacco consumption.
Diagnosis of PKD
Diagnostic tests performed in autosomal dominant PKD are:
Which family members of PKD patients should be screened for PKD?
Brothers, sisters and children of PKD patients should be screened for PKD. In addition, brothers and sisters of parents from whom the disease is inherited by the patient should be screened.
Will all children of PKD patients carry the risk of developing the same disease?
No. PKD is an inherited disease in which if mother or father has autosomal dominant PKD, the children have a 50% possibility of developing the disorder.