Polycystic kidney disease, often referred to as PKD, is an inherited condition in which large, fluid-filled, baglike growths called cysts develop in the kidney. PKD eventually leads to destruction of the kidney. The most common form is called autosomal dominant polycystic kidney disease (ADPKD). A child of a parent with ADPKD has a 1-in-2 chance of being affected by the disease. It is one of the most common inherited diseases in human beings. ADPKD is caused by a mutation in either of two genes: PKD1 or PKD2.
In ADPKD, cysts typically appear in the kidney by the age of 30. Patients may also develop cysts arising from the bile ducts in the liver. Complications from ADPKD include pain from the growth, rupture, bleeding, or infection of kidney cysts or from kidney stones. There is no specific cure for ADPKD, but treatment can ease symptoms and prolong life. Most patients develop hypertension (high blood pressure), which requires treatment with medication. About half of all patients require the use of a dialysis machine or a kidney transplant by age 60.
Another form of PKD, autosomal recessive polycystic kidney disease (ARPKD), is a rare condition that mainly affects children. It can cause death shortly after birth. Among surviving children, it will eventually result in liver or kidney failure. Hypertension is also common.
In PKD, kidney cells lack critical proteins produced by the normal PKD1 and PKD2 genes. These proteins, called polycystins, are necessary for the normal function of cilia, single threadlike projections of the cell membrane of each kidney cell. Lack of polycystins triggers a process by which some cells change properties and, over the years, grow into large cysts.
See also Kidney .
