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Genetics Home Reference: your guide to understanding genetic conditions
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Familial adenomatous polyposis

Reviewed October 2013

What is familial adenomatous polyposis?

Familial adenomatous polyposis (FAP) is an inherited disorder characterized by cancer of the large intestine (colon) and rectum. People with the classic type of familial adenomatous polyposis may begin to develop multiple noncancerous (benign) growths (polyps) in the colon as early as their teenage years. Unless the colon is removed, these polyps will become malignant (cancerous). The average age at which an individual develops colon cancer in classic familial adenomatous polyposis is 39 years. Some people have a variant of the disorder, called attenuated familial adenomatous polyposis, in which polyp growth is delayed. The average age of colorectal cancer onset for attenuated familial adenomatous polyposis is 55 years.

In people with classic familial adenomatous polyposis, the number of polyps increases with age, and hundreds to thousands of polyps can develop in the colon. Also of particular significance are noncancerous growths called desmoid tumors. These fibrous tumors usually occur in the tissue covering the intestines and may be provoked by surgery to remove the colon. Desmoid tumors tend to recur after they are surgically removed. In both classic familial adenomatous polyposis and its attenuated variant, benign and malignant tumors are sometimes found in other places in the body, including the duodenum (a section of the small intestine), stomach, bones, skin, and other tissues. People who have colon polyps as well as growths outside the colon are sometimes described as having Gardner syndrome.

A milder type of familial adenomatous polyposis, called autosomal recessive familial adenomatous polyposis, has also been identified. People with the autosomal recessive type of this disorder have fewer polyps than those with the classic type. Fewer than 100 polyps typically develop, rather than hundreds or thousands. The autosomal recessive type of this disorder is caused by mutations in a different gene than the classic and attenuated types of familial adenomatous polyposis.

How common is familial adenomatous polyposis?

The reported incidence of familial adenomatous polyposis varies from 1 in 7,000 to 1 in 22,000 individuals.

What genes are related to familial adenomatous polyposis?

Mutations in the APC gene cause both classic and attenuated familial adenomatous polyposis. These mutations affect the ability of the cell to maintain normal growth and function. Cell overgrowth resulting from mutations in the APC gene leads to the colon polyps seen in familial adenomatous polyposis. Although most people with mutations in the APC gene will develop colorectal cancer, the number of polyps and the time frame in which they become malignant depend on the location of the mutation in the gene.

Mutations in the MUTYH gene cause autosomal recessive familial adenomatous polyposis (also called MYH-associated polyposis). Mutations in this gene prevent cells from correcting mistakes that are made when DNA is copied (DNA replication) in preparation for cell division. As these mistakes build up in a person's DNA, the likelihood of cell overgrowth increases, leading to colon polyps and the possibility of colon cancer.

Related Gene(s)

Changes in these genes are associated with familial adenomatous polyposis.

  • APC
  • MUTYH

How do people inherit familial adenomatous polyposis?

Familial adenomatous polyposis can have different inheritance patterns.

When familial adenomatous polyposis results from mutations in the APC gene, it is inherited in an autosomal dominant pattern, which means one copy of the altered gene in each cell is sufficient to cause the disorder. In most cases, an affected person has one parent with the condition.

When familial adenomatous polyposis results from mutations in the MUTYH gene, it is inherited in an autosomal recessive pattern, which means both copies of the gene in each cell have mutations. Most often, the parents of an individual with an autosomal recessive condition each carry one copy of the mutated gene, but do not show signs and symptoms of the condition.

Where can I find information about diagnosis or management of familial adenomatous polyposis?

These resources address the diagnosis or management of familial adenomatous polyposis and may include treatment providers.

  • American Medical Association and National Coalition for Health Professional Education in Genetics: Understand the Basics of Genetic Testing for Hereditary Colorectal Cancer (http://www.nchpeg.org/documents/crc/Basics%20of%20genetic%20testing.pdf)
  • GeneFacts: Familial Adenomatous Polyposis: Diagnosis (http://genefacts.org/index.php?option=com_content&view=article&id=602&Itemid=751)
  • GeneFacts: Familial Adenomatous Polyposis: Management (http://genefacts.org/index.php?option=com_content&view=article&id=603&Itemid=752)
  • Gene Review: APC-Associated Polyposis Conditions (http://www.ncbi.nlm.nih.gov/books/NBK1345/)
  • Gene Review: MUTYH-Associated Polyposis (http://www.ncbi.nlm.nih.gov/books/NBK107219/)
  • Genetic Testing Registry: Adenomatous polyposis coli (http://www.ncbi.nlm.nih.gov/gtr/conditions/CN074282)
  • Genetic Testing Registry: Desmoid disease, hereditary (http://www.ncbi.nlm.nih.gov/gtr/conditions/C1851124)
  • Genetic Testing Registry: Familial multiple polyposis syndrome (http://www.ncbi.nlm.nih.gov/gtr/conditions/C0032580)
  • Genetic Testing Registry: MYH-associated polyposis (http://www.ncbi.nlm.nih.gov/gtr/conditions/C1837991)
  • MedlinePlus Encyclopedia: Colon Cancer (http://www.nlm.nih.gov/medlineplus/ency/article/000262.htm)
  • MedlinePlus Encyclopedia: Colorectal polyps (http://www.nlm.nih.gov/medlineplus/ency/article/000266.htm)
  • National Cancer Institute: Genetic Testing for Hereditary Cancer Syndromes (http://www.cancer.gov/cancertopics/factsheet/Risk/genetic-testing)

You might also find information on the diagnosis or management of familial adenomatous polyposis in Educational resources (http://www.ghr.nlm.nih.gov/condition/familial-adenomatous-polyposis/show/Educational+resources) and Patient support (http://www.ghr.nlm.nih.gov/condition/familial-adenomatous-polyposis/show/Patient+support).

General information about the diagnosis (http://ghr.nlm.nih.gov/handbook/consult/diagnosis) and management (http://ghr.nlm.nih.gov/handbook/consult/treatment) of genetic conditions is available in the Handbook. Read more about genetic testing (http://ghr.nlm.nih.gov/handbook/testing), particularly the difference between clinical tests and research tests (http://ghr.nlm.nih.gov/handbook/testing/researchtesting).

To locate a healthcare provider, see How can I find a genetics professional in my area? (http://ghr.nlm.nih.gov/handbook/consult/findingprofessional) in the Handbook.

Where can I find additional information about familial adenomatous polyposis?

You may find the following resources about familial adenomatous polyposis helpful. These materials are written for the general public.

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

What other names do people use for familial adenomatous polyposis?

  • adenomatous familial polyposis
  • adenomatous familial polyposis syndrome
  • adenomatous polyposis coli
  • familial multiple polyposis syndrome
  • FAP
  • MYH-associated polyposis

For more information about naming genetic conditions, see the Genetics Home Reference Condition Naming Guidelines (http://ghr.nlm.nih.gov/ConditionNameGuide) and How are genetic conditions and genes named? (http://ghr.nlm.nih.gov/handbook/mutationsanddisorders/naming) in the Handbook.

What if I still have specific questions about familial adenomatous polyposis?

Ask the Genetic and Rare Diseases Information Center (http://rarediseases.info.nih.gov/GARD/).

What glossary definitions help with understanding familial adenomatous polyposis?

autosomal ; autosomal dominant ; autosomal recessive ; benign ; cancer ; cell ; cell division ; colon ; colorectal ; desmoid ; DNA ; DNA replication ; duodenum ; familial ; gene ; incidence ; inheritance ; intestine ; mutation ; polyp ; polyposis ; recessive ; rectum ; stomach ; surgery ; syndrome ; teenage ; tissue

You may find definitions for these and many other terms in the Genetics Home Reference Glossary (http://www.ghr.nlm.nih.gov/glossary).

References

  • Attard TM, Cuffari C, Tajouri T, Stoner JA, Eisenberg MT, Yardley JH, Abraham SC, Perry D, Vanderhoof J, Lynch H. Multicenter experience with upper gastrointestinal polyps in pediatric patients with familial adenomatous polyposis. Am J Gastroenterol. 2004 Apr;99(4):681-6. (http://www.ncbi.nlm.nih.gov/pubmed/15089902?dopt=Abstract)
  • Baglioni S, Genuardi M. Simple and complex genetics of colorectal cancer susceptibility. Am J Med Genet C Semin Med Genet. 2004 Aug 15;129C(1):35-43. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15264271?dopt=Abstract)
  • Bienz M. APC. Curr Biol. 2003 Mar 18;13(6):R215-6. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12646143?dopt=Abstract)
  • Cheadle JP, Sampson JR. Exposing the MYtH about base excision repair and human inherited disease. Hum Mol Genet. 2003 Oct 15;12 Spec No 2:R159-65. Epub 2003 Aug 5. Review. (http://www.ncbi.nlm.nih.gov/pubmed/12915454?dopt=Abstract)
  • Claes K, Dahan K, Tejpar S, De Paepe A, Bonduelle M, Abramowicz M, Verellen C, Franchimont D, Van Cutsem E, Kartheuser A. The genetics of familial adenomatous polyposis (FAP) and MutYH-associated polyposis (MAP). Acta Gastroenterol Belg. 2011 Sep;74(3):421-6. Review. (http://www.ncbi.nlm.nih.gov/pubmed/22103048?dopt=Abstract)
  • Crabtree M, Sieber OM, Lipton L, Hodgson SV, Lamlum H, Thomas HJ, Neale K, Phillips RK, Heinimann K, Tomlinson IP. Refining the relation between 'first hits' and 'second hits' at the APC locus: the 'loose fit' model and evidence for differences in somatic mutation spectra among patients. Oncogene. 2003 Jul 3;22(27):4257-65. (http://www.ncbi.nlm.nih.gov/pubmed/12833148?dopt=Abstract)
  • Järvinen HJ, Peltomäki P. The complex genotype-phenotype relationship in familial adenomatous polyposis. Eur J Gastroenterol Hepatol. 2004 Jan;16(1):5-8. (http://www.ncbi.nlm.nih.gov/pubmed/15095846?dopt=Abstract)
  • Knudsen AL, Bisgaard ML, Bülow S. Attenuated familial adenomatous polyposis (AFAP). A review of the literature. Fam Cancer. 2003;2(1):43-55. Review. (http://www.ncbi.nlm.nih.gov/pubmed/14574166?dopt=Abstract)
  • Lipton L, Tomlinson I. The multiple colorectal adenoma phenotype and MYH, a base excision repair gene. Clin Gastroenterol Hepatol. 2004 Aug;2(8):633-8. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15290654?dopt=Abstract)
  • Lucci-Cordisco E, Risio M, Venesio T, Genuardi M. The growing complexity of the intestinal polyposis syndromes. Am J Med Genet A. 2013 Nov;161A(11):2777-87. doi: 10.1002/ajmg.a.36253. Epub 2013 Oct 3. (http://www.ncbi.nlm.nih.gov/pubmed/24124059?dopt=Abstract)
  • Lynch HT, Shaw TG, Lynch JF. Inherited predisposition to cancer: a historical overview. Am J Med Genet C Semin Med Genet. 2004 Aug 15;129C(1):5-22. (http://www.ncbi.nlm.nih.gov/pubmed/15264268?dopt=Abstract)
  • National Cancer Institute: Genetics of Colorectal Cancer (http://www.cancer.gov/cancertopics/pdq/genetics/colorectal/HealthProfessional/page1)
  • Rowley PT. Inherited susceptibility to colorectal cancer. Annu Rev Med. 2005;56:539-54. Review. (http://www.ncbi.nlm.nih.gov/pubmed/15660526?dopt=Abstract)
  • Rustgi AK. The genetics of hereditary colon cancer. Genes Dev. 2007 Oct 15;21(20):2525-38. Review. (http://www.ncbi.nlm.nih.gov/pubmed/17938238?dopt=Abstract)
  • Sampson JR, Dolwani S, Jones S, Eccles D, Ellis A, Evans DG, Frayling I, Jordan S, Maher ER, Mak T, Maynard J, Pigatto F, Shaw J, Cheadle JP. Autosomal recessive colorectal adenomatous polyposis due to inherited mutations of MYH. Lancet. 2003 Jul 5;362(9377):39-41. (http://www.ncbi.nlm.nih.gov/pubmed/12853198?dopt=Abstract)
  • Sieber OM, Lipton L, Crabtree M, Heinimann K, Fidalgo P, Phillips RK, Bisgaard ML, Orntoft TF, Aaltonen LA, Hodgson SV, Thomas HJ, Tomlinson IP. Multiple colorectal adenomas, classic adenomatous polyposis, and germ-line mutations in MYH. N Engl J Med. 2003 Feb 27;348(9):791-9. (http://www.ncbi.nlm.nih.gov/pubmed/12606733?dopt=Abstract)
  • Wang L, Baudhuin LM, Boardman LA, Steenblock KJ, Petersen GM, Halling KC, French AJ, Johnson RA, Burgart LJ, Rabe K, Lindor NM, Thibodeau SN. MYH mutations in patients with attenuated and classic polyposis and with young-onset colorectal cancer without polyps. Gastroenterology. 2004 Jul;127(1):9-16. Erratum in: Gastroenterology. 2004 Nov;127(5):1651. (http://www.ncbi.nlm.nih.gov/pubmed/15236166?dopt=Abstract)

 

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.

 
Reviewed: October 2013
Published: July 7, 2014