Selection criteria for families with parent-offspring pairs for study. The polycystic kidney disease (PKD) database at University of Colorado Health Sciences Center containing 1,228 PKD families with 4,618 individuals was queried, and 413 families (2,409 affected) with 1,807 parent-offspring pairs for potential analysis were identified. Detailed distribution of the 1,391 parent-offspring pairs informative for age at end-stage renal disease (ESRD) or last known age without ESRD identified is listed in Table 2. Abbreviation: ADPKD, autosomal dominant PKD.