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The official name of this gene is “polycystic kidney disease 2 (autosomal dominant).”
PKD2 is the gene's official symbol. The PKD2 gene is also known by other names, listed below.
The PKD2 gene provides instructions for making a protein called polycystin-2. This protein is found in the kidneys before birth and in many adult tissues. Although its exact function is not well understood, polycystin-2 can be regulated by a larger, somewhat similar protein called polycystin-1.
Polycystin-2 likely functions as a channel spanning the cell membrane of kidney cells. In conjunction with polycystin-1, the channel transports positively charged atoms (ions), particularly calcium ions, into the cell. This influx of calcium ions triggers a cascade of chemical reactions inside the cell that may instruct the cell to undergo certain changes, such as maturing to take on specialized functions. Polycystin-1 and polycystin-2 likely work together to help regulate cell growth and division (proliferation), cell movement (migration), and interactions with other cells.
Polycystin-2 is also active in other parts of the cell, including cellular structures called primary cilia. Primary cilia are tiny, fingerlike projections that line the small tubes where urine is formed (renal tubules). Researchers believe that primary cilia sense the movement of fluid through these tubules, which appears to help maintain the tubules' size and structure. The interaction of polycystin-1 and polycystin-2 in renal tubules promotes the normal development and function of the kidneys.
The PKD2 gene belongs to a family of genes called EF-hand domain containing (EF-hand domain containing). It also belongs to a family of genes called TRP (transient receptor potential cation channels).
A gene family is a group of genes that share important characteristics. Classifying individual genes into families helps researchers describe how genes are related to each other. For more information, see What are gene families? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genefamilies) in the Handbook.
More than 75 mutations in the PKD2 gene have been identified in people with polycystic kidney disease. These mutations are responsible for about 15 percent of all cases of autosomal dominant polycystic kidney disease (ADPKD), which is the most common type of this disorder. Mutations in the PKD2 gene include changes in single DNA building blocks (base pairs) and deletions or insertions of a small number of base pairs in the gene. Most PKD2 mutations are predicted to result in the production of an abnormally small, nonfunctional version of the polycystin-2 protein. Although researchers are uncertain how a lack of polycystin-2 leads to the formation of cysts, it likely disrupts the protein's interaction with polycystin-1 and alters signaling within the cell and in primary cilia. As a result, cells lining the renal tubules may grow and divide abnormally, leading to the growth of numerous cysts characteristic of polycystic kidney disease.
Cytogenetic Location: 4q22.1
Molecular Location on chromosome 4: base pairs 88,007,646 to 88,077,778
The PKD2 gene is located on the long (q) arm of chromosome 4 at position 22.1.
More precisely, the PKD2 gene is located from base pair 88,007,646 to base pair 88,077,778 on chromosome 4.
See How do geneticists indicate the location of a gene? (http://ghr.nlm.nih.gov/handbook/howgeneswork/genelocation) in the Handbook.
You and your healthcare professional may find the following resources about PKD2 helpful.
You may also be interested in these resources, which are designed for genetics professionals and researchers.
See How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.
autosomal ; autosomal dominant ; calcium ; cation ; cell ; cell membrane ; channel ; cysts ; DNA ; gene ; ions ; kidney ; polycystic kidney ; proliferation ; protein ; renal
You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).
The resources on this site should not be used as a substitute for professional medical care or advice. Users seeking information about a personal genetic disease, syndrome, or condition should consult with a qualified healthcare professional. See How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.