Autosomal dominant polycystic kidney disease (ADPKD) affects between 1 in 400 and 1 in 1000 individuals and is one of the most common hereditary diseases. Two types have been defined. ADPKD 1 is the commonest and responsible for about 85% of cases. It is due to a mutation in the PKD1 gene on chromosome 16, which encodes polycystin 1, an *ion-channel-regulating protein. ADPKD2 is due to a mutation in the PKD2 gene on chromosome 4, which encodes the protein polycystin 2, a calcium-release channel. ADPKD2 tends to be a milder disease with later presentation.
ADPKD is a multisystem disorder that is also associated with cyst formation in other organs (particularly the liver), cardiovascular disorders, and colonic diverticular disease. Renal disease presents in early adult life with haematuria, loin pain, urinary tract infection, hypertension, renal stone disease, or the finding of a mass in the abdomen. Other cases are identified by family contact tracing; the findings of a few cysts on renal ultrasonography in a young adult with a family history of ADPKD is highly suggestive of the disease. Renal disease is progressive and about 50% of patients will have reached end-stage by the time they enter their seventh decade. The progress of the renal failure can be slowed by good blood pressure control. In the UK, patients with ADPKD are responsible for 5–10% of the total on renal replacement therapy.
There are a number of separate rare autosomal dominant conditions other than ADPKD1 and ADPKD 2 that can present with polycystic kidneys. These include *von Hippel-Lindau disease and *tuberous sclerosis.... polycystic disease of the kidneys