Although renal cysts are present in a wide variety of renal diseases in children, the term polycystic kidney disease is reserved for the following hereditary conditions:
- Autosomal recessive polycystic kidney disease (ARPKD, previously called infantile polycystic kidney disease) is a recessive inherited disorder characterized by cystic dilations of the renal collecting ducts and congenital hepatic fibrosis.
- Autosomal dominant polycystic kidney disease (ADPKD, previously termed adult polycystic kidney disease) is a dominant inherited disorder characterized by cystic dilations in all parts of the nephron. Cysts in the liver and pancreas are also common in ADPKD. Most patients with ADPKD present as adults; however, some patients present in early childhood and even as early as in utero.
The clinical features, diagnosis, and management of ADPKD in children will be reviewed here. Discussions on other cystic diseases including ARPKD are found separately in the program. (See "Autosomal recessive polycystic kidney disease in children" and "Renal cystic diseases in children".)
The incidence of ADPKD is greater than ARPKD, occurring in one in every 400 to 1000 live births. ADPKD accounts for more than 5 percent of cases of end-stage renal disease in Europe and North America.
A mutation in the PKD1 gene, which is located on chromosome 16 and encodes polycystin 1, is present in 85 percent of patients with ADPKD. Most other patients with ADPKD have a mutation in the PKD2 gene, which encodes polycystin 2 and is located on chromosome 4. Both proteins are involved with cell calcium signaling and localize to the primary cilia of renal epithelial cells. The genetics and pathogenesis of ADPKD are discussed separately. (See "Genetics of autosomal dominant polycystic kidney disease and mechanisms of cyst growth".)