Polycystic kidney disease (PKD or PCKD, also known as polycystic kidney syndrome) is a genetic disorder in which the renal tubules become structurally abnormal, resulting in the development and growth of multiple cysts within the kidney.[5] These cysts may begin to develop in utero, in infancy, in childhood, or in adulthood.[6] Cysts are non-functioning tubules filled with fluid pumped into them, which range in size from microscopic to enormous, crushing adjacent normal tubules and eventually rendering them non-functional as well.

Autosomal dominant polycystic kidney disease (ADPKD) is the most common of all the inherited cystic kidney diseases[10][11][12] with an incidence of 1:500 live births.[10][12] Studies show that 10% of end-stage kidney disease (ESKD) patients being treated with dialysis in Europe and the U.S. were initially diagnosed and treated for ADPKD.[10][9]

There are three genetic mutations in the PKD-1, PKD-2, and PKD3 gene with similar phenotypical presentations.

Gene PKD1 is located on chromosome 16 and codes for a protein involved in regulation of cell cycle and intracellular calcium transport in epithelial cells, and is responsible for 85% of the cases of ADPKD.

A group of voltage-linked calcium channels are coded for by PKD2 on chromosome 4.

PKD3 recently appeared in research papers as a postulated third gene.[10][11] Fewer than 10% of cases of ADPKD appear in non-ADPKD families. Cyst formation begins in utero from any point along the nephron, although fewer than 5% of nephrons are thought to be involved. As the cysts accumulate fluid, they enlarge, separate entirely from the nephron, compress the neighboring kidney parenchyma, and progressively compromise kidney function.[medical citation needed][9]

Autosomal recessive Edit

Autosomal recessive polycystic kidney disease (ARPKD) (OMIM #263200) is the lesser common of the two types of PKD, with an incidence of 1:20,000 live births and is typically identified in the first few weeks after birth. Unfortunately, the kidneys are often underdeveloped resulting in a 30% death rate in newborns with ARPKD.[10][9]