http://kidney.niddk.nih.gov/kudiseases/pubs/polycystic/
National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health
Polycystic kidney disease (PKD) is a genetic disorder characterized by the growth of numerous cysts in the kidneys. The cysts are filled with fluid. PKD cysts can slowly replace much of the mass of the kidneys, reducing kidney function and leading to kidney failure.