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Genetics Home Reference: your guide to understanding genetic conditions     A service of the U.S. National Library of Medicine®


Reviewed May 2010

What is the official name of the XPC gene?

The official name of this gene is “xeroderma pigmentosum, complementation group C.”

XPC is the gene's official symbol. The XPC gene is also known by other names, listed below.

What is the normal function of the XPC gene?

The XPC gene provides instructions for making a protein that is involved in repairing damaged DNA. DNA can be damaged by ultraviolet (UV) rays from the sun and by toxic chemicals, radiation, and unstable molecules called free radicals.

DNA damage occurs frequently, but normal cells are usually able to fix it before it can cause problems. One of the major mechanisms that cells use to fix DNA is known as nucleotide excision repair (NER). The XPC protein starts this repair process by detecting DNA damage. Then a group (complex) of other proteins unwind the section of DNA where the damage has occurred, snip out (excise) the abnormal section, and replace the damaged area with the correct DNA.

Studies suggest that the XPC protein may have additional roles in DNA repair and in other cell activities. Less is known about these proposed functions of the XPC protein.

How are changes in the XPC gene related to health conditions?

xeroderma pigmentosum - caused by mutations in the XPC gene

More than 40 mutations in the XPC gene have been found to cause xeroderma pigmentosum. Mutations in this gene are the most common cause of this disorder in the United States and Europe.

Most XPC gene mutations prevent the production of any XPC protein. A loss of this protein keeps cells from repairing DNA damage normally. As a result, abnormalities accumulate in DNA, causing cells to malfunction and eventually to become cancerous or die. These problems with DNA repair cause people with xeroderma pigmentosum to be extremely sensitive to UV rays from sunlight. When UV rays damage genes that control cell growth and division, cells can grow too fast and in an uncontrolled way. As a result, people with xeroderma pigmentosum have a greatly increased risk of developing cancer. These cancers occur most frequently in areas of the body that are exposed to the sun, such as the skin and eyes.

Unlike some of the other forms of xeroderma pigmentosum, when the disorder is caused by mutations in the XPC gene it is generally not associated with neurological abnormalities (such as delayed development and hearing loss). It is unclear why some people with xeroderma pigmentosum develop neurological abnormalities and others do not.

Where is the XPC gene located?

Cytogenetic Location: 3p25.1

Molecular Location on chromosome 3: base pairs 14,145,147 to 14,178,672

(Homo sapiens Annotation Release 107, GRCh38.p2) (NCBI (

The XPC gene is located on the short (p) arm of chromosome 3 at position 25.1.

The XPC gene is located on the short (p) arm of chromosome 3 at position 25.1.

More precisely, the XPC gene is located from base pair 14,145,147 to base pair 14,178,672 on chromosome 3.

See How do geneticists indicate the location of a gene? ( in the Handbook.

Where can I find additional information about XPC?

You and your healthcare professional may find the following resources about XPC helpful.

You may also be interested in these resources, which are designed for genetics professionals and researchers.

What other names do people use for the XPC gene or gene products?

  • RAD4
  • Xeroderma pigmentosum group C-complementing protein
  • XP3
  • XPCC

See How are genetic conditions and genes named? ( in the Handbook.

What glossary definitions help with understanding XPC?

cancer ; cell ; DNA ; DNA damage ; DNA repair ; free radicals ; gene ; genome ; NER ; neurological ; nucleotide ; nucleotide excision repair ; protein ; radiation ; toxic ; UV rays

You may find definitions for these and many other terms in the Genetics Home Reference Glossary.


  • Bernardes de Jesus BM, Bjørås M, Coin F, Egly JM. Dissection of the molecular defects caused by pathogenic mutations in the DNA repair factor XPC. Mol Cell Biol. 2008 Dec;28(23):7225-35. doi: 10.1128/MCB.00781-08. Epub 2008 Sep 22. (
  • Chavanne F, Broughton BC, Pietra D, Nardo T, Browitt A, Lehmann AR, Stefanini M. Mutations in the XPC gene in families with xeroderma pigmentosum and consequences at the cell, protein, and transcript levels. Cancer Res. 2000 Apr 1;60(7):1974-82. (
  • Cleaver JE, Thompson LH, Richardson AS, States JC. A summary of mutations in the UV-sensitive disorders: xeroderma pigmentosum, Cockayne syndrome, and trichothiodystrophy. Hum Mutat. 1999;14(1):9-22. Review. (
  • D'Errico M, Parlanti E, Teson M, de Jesus BM, Degan P, Calcagnile A, Jaruga P, Bjørås M, Crescenzi M, Pedrini AM, Egly JM, Zambruno G, Stefanini M, Dizdaroglu M, Dogliotti E. New functions of XPC in the protection of human skin cells from oxidative damage. EMBO J. 2006 Sep 20;25(18):4305-15. Epub 2006 Sep 7. (
  • Hoogstraten D, Bergink S, Ng JM, Verbiest VH, Luijsterburg MS, Geverts B, Raams A, Dinant C, Hoeijmakers JH, Vermeulen W, Houtsmuller AB. Versatile DNA damage detection by the global genome nucleotide excision repair protein XPC. J Cell Sci. 2008 Sep 1;121(Pt 17):2850-9. doi: 10.1242/jcs.031708. Epub 2008 Aug 5. Erratum in: J Cell Sci. 2008 Dec 1;121(Pt 23):3991. Ng, Jessica M Y [added]. J Cell Sci. 2008 Sep 1;121(Pt 17):2972. (
  • Khan SG, Oh KS, Shahlavi T, Ueda T, Busch DB, Inui H, Emmert S, Imoto K, Muniz-Medina V, Baker CC, DiGiovanna JJ, Schmidt D, Khadavi A, Metin A, Gozukara E, Slor H, Sarasin A, Kraemer KH. Reduced XPC DNA repair gene mRNA levels in clinically normal parents of xeroderma pigmentosum patients. Carcinogenesis. 2006 Jan;27(1):84-94. Epub 2005 Aug 4. (
  • NCBI Gene (
  • Sugasawa K. UV-induced ubiquitylation of XPC complex, the UV-DDB-ubiquitin ligase complex, and DNA repair. J Mol Histol. 2006 Sep;37(5-7):189-202. Epub 2006 Jul 21. Review. (
  • Sugasawa K. XPC: its product and biological roles. Adv Exp Med Biol. 2008;637:47-56. Review. (


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? ( in the Handbook.

Reviewed: May 2010
Published: February 8, 2016