The purpose of this study is to establish a prospective observational cohort of 200 well-characterized adults with ADPKD, and an associated biorepository of DNA, plasma, serum, and urine. Baseline clinical phenotyping includes measurement of renal filtration function, total kidney volume, clinical and family history, presence and history of renal and extra-renal ADPKD manifestations, cardiac function, vascular stiffness, and health-related quality of life.