Autosomal Dominant Polycystic Kidney Disease (ADPKD) affects up to 12 million individuals and is the 4th most common cause for renal replacement therapy worldwide. There have been many recent advances in the understanding of its molecular genetics and biology, and in the diagnosis and management of its manifestations. Yet, diagnosis, evaluation, prevention and treatment vary widely and there are no broadly accepted practice guidelines. Barriers to translation of basic science breakthroughs to clinical care exist, with considerable heterogeneity across countries. The KDIGO Controversies Conference on ADPKD brought together a panel of multi-disciplinary clinical expertise and engaged patients to identify areas of consensus, gaps in knowledge, and research and health care priorities related to diagnosis, monitoring of kidney disease progression, management of hypertension, renal function decline and complications, end-stage renal disease, extrarenal complications, and practical integrated patient support. These are summarized in this report.

Autosomal dominant polycystic kidney disease (ADPKD) is a common disease and an important cause of renal failure. It is characterized by considerable intrafamilial phenotypic variation and focal cyst formation. To elucidate the molecular basis for these observations, we have developed a novel method for isolating renal cystic epithelia from single cysts and have used it to show that individual renal cysts in ADPKD are monoclonal. Loss of heterozygosity was discovered within a subset of cysts for two closely linked polymorphic markers located within the PKD1 gene. Genetic analysis revealed that it was the normal haplotype that was lost. This study provides a molecular explanation for the focal nature of cyst formation and a probable mechanism whereby mutations cause disease. The high rate at which "second hits" must occur to account for the large number of cysts observed suggests that unique structural features of the PKD1 gene may be responsible for its mutability.

Polycystin-1 plays an essential role in renal tubular morphogenesis, and disruption of its function causes cystogenesis in human autosomal-dominant polycystic kidney disease (ADPKD). We demonstrated that polycystin-1 undergoes cleavage at G protein coupled receptor proteolytic site in a process that requires the receptor for egg jelly domain. Most of the N-terminal fragment remains tethered at the cell surface, although a small amount is secreted. PKD1-associated mutations in the receptor for egg jelly domain disrupt cleavage, abolish the ability of polycystin-1 to activate signal transducer and activator of transcription-1, and induce tubulogenesis in vitro. We conclude that the cleavage of polycystin-1 is likely essential for its biologic activity.