Send to:

Choose Destination

Links from PubMed

Familial adenomatous polyposis 1(FAP1)

MedGen UID:
Concept ID:
Disease or Syndrome
Synonyms: APC-Associated Polyposis Conditions; Colon Cancer (APC I1307K related); Familial Adenomatous Polyposis; FAMILIAL ADENOMATOUS POLYPOSIS 1, ATTENUATED; FAP1; POLYPOSIS, ADENOMATOUS INTESTINAL
Modes of inheritance:
Autosomal dominant inheritance
MedGen UID:
Concept ID:
Intellectual Product
Sources: HPO, OMIM, Orphanet
A mode of inheritance that is observed for traits related to a gene encoded on one of the autosomes (i.e., the human chromosomes 1-22) in which a trait manifests in heterozygotes. In the context of medical genetics, an autosomal dominant disorder is caused when a single copy of the mutant allele is present. Males and females are affected equally, and can both transmit the disorder with a risk of 50% for each child of inheriting the mutant allele.
Autosomal dominant inheritance (HPO, OMIM, Orphanet)
Gene (location): APC (5q22.2)
Related genes: PMS2, MSH2, MLH1, MSH6
OMIM®: 175100

Disease characteristics

Excerpted from the GeneReview: APC-Associated Polyposis Conditions
APC-associated polyposis conditions include: familial adenomatous polyposis (FAP), attenuated FAP, and gastric adenocarcinoma and proximal polyposis of the stomach (GAPPS). FAP is a colon cancer predisposition syndrome in which hundreds to thousands of adenomatous colonic polyps develop, beginning, on average, at age 16 years (range 7-36 years). By age 35 years, 95% of individuals with FAP have polyps; without colectomy, colon cancer is inevitable. The mean age of colon cancer diagnosis in untreated individuals is 39 years (range 34-43 years). Extracolonic manifestations are variably present and include: polyps of the gastric fundus and duodenum, osteomas, dental anomalies, congenital hypertrophy of the retinal pigment epithelium (CHRPE), soft tissue tumors, desmoid tumors, and associated cancers. Attenuated FAP is characterized by multiple colonic polyps (average of 30), more proximally located polyps, and a diagnosis of colon cancer at a later age than in FAP. Certain extracolonic manifestations, such as gastric and duodenal polyps or cancers, are variably present in attenuated FAP; risk management may be substantially different between FAP and attenuated FAP. GAPPS is characterized by gastric fundic gland polyposis, increased risk of gastric cancer, and limited colonic involvement in most individuals reported. [from GeneReviews]
Kory W Jasperson  |  Swati G Patel  |  Dennis J Ahnen   view full author information

Additional descriptions

Familial adenomatous polyposis-1 is an autosomal dominant disorder characterized by predisposition to cancer. Affected individuals usually develop hundreds to thousands of adenomatous polyps of the colon and rectum, a small proportion of which will progress to colorectal carcinoma if not surgically treated. Gardner syndrome is a variant of FAP in which desmoid tumors, osteomas, and other neoplasms occur together with multiple adenomas of the colon and rectum (Nishisho et al., 1991). Rustgi (2007) reviewed the genetics of hereditary colon cancer, including APC. Genetic Heterogeneity of Familial Adenomatous Polyposis See also autosomal recessive FAP2 (608456), caused by mutation in the MUTYH gene (604933) on chromosome 1p34; autosomal recessive FAP3 (616415), caused by mutation in the NTHL1 gene (602656) on chromosome 16p13; and autosomal recessive FAP4 (617100), caused by mutation in the MSH3 gene (600887) on chromosome 5q11.
From GHR
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.

Clinical features

MedGen UID:
Concept ID:
Neoplastic Process
A glial tumor of the brain or spinal cord showing astrocytic differentiation. It includes the following clinicopathological entities: pilocytic astrocytoma, diffuse astrocytoma, anaplastic astrocytoma, pleomorphic xanthoastrocytoma, subependymal giant cell astrocytoma, and glioblastoma.
Keloid formation
MedGen UID:
Concept ID:
Acquired Abnormality
Keloid is a dermal fibroproliferative growth caused by pathologic wound healing following skin injury. Keloid is defined as a scar growing continuously and invasively beyond the confines of the original wound and is characterized by excessive fibroblast proliferation and deposition of extracellular matrix and collagen fibers. Local tissue factors, especially wound tension or infection, and endocrine factors are known to be involved in keloid formation. However, the fact that the incidence of keloid is higher in darker-skinned individuals suggests that genetic factors also play an important role (summary by Nakashima et al., 2010).
MedGen UID:
Concept ID:
Neoplastic Process
A benign, slow growing, and painless hamartomatous tumor occurring in tooth-bearing areas of the jaws. According to the presence or absence of tooth-like structures, it is classified as complex type or compound type. Odontoma of complex type is characterized by the presence of enamel and dentin and the absence of tooth-like structures. It is treated with local excision. If it is incompletely removed, it may recur. Odontoma of compound type is characterized by the presence of tooth-like structures. It is treated by local excision. Recurrences have not been reported.
Hyperpigmentation of the skin
MedGen UID:
Concept ID:
Pathologic Function
A darkening of the skin related to an increase in melanin production and deposition.
Adrenocortical carcinoma
MedGen UID:
Concept ID:
Neoplastic Process
A malignant neoplasm of the ADRENAL CORTEX. Adrenocortical carcinomas are unencapsulated anaplastic (ANAPLASIA) masses sometimes exceeding 20 cm or 200 g. They are more likely to be functional than nonfunctional, and produce ADRENAL CORTEX HORMONES that may result in hypercortisolism (CUSHING SYNDROME); HYPERALDOSTERONISM; and/or VIRILISM.
Multiple lipomas
MedGen UID:
Concept ID:
The presence of multiple lipomas (a type of benign tissue made of fatty tissue).
Small intestine carcinoid
MedGen UID:
Concept ID:

Term Hierarchy

Professional guidelines


Syngal S, Brand RE, Church JM, Giardiello FM, Hampel HL, Burt RW; American College of Gastroenterology.
Am J Gastroenterol 2015 Feb;110(2):223-62; quiz 263. Epub 2015 Feb 3 doi: 10.1038/ajg.2014.435. PMID: 25645574Free PMC Article
Stoffel EM, Mangu PB, Gruber SB, Hamilton SR, Kalady MF, Lau MW, Lu KH, Roach N, Limburg PJ; American Society of Clinical Oncology.; European Society of Clinical Oncology.
J Clin Oncol 2015 Jan 10;33(2):209-17. Epub 2014 Dec 1 doi: 10.1200/JCO.2014.58.1322. PMID: 25452455Free PMC Article
ACMG Board of Directors.
Genet Med 2015 Jan;17(1):68-9. Epub 2014 Nov 13 doi: 10.1038/gim.2014.151. PMID: 25356965
Hegde M, Ferber M, Mao R, Samowitz W, Ganguly A; Working Group of the American College of Medical Genetics and Genomics (ACMG) Laboratory Quality Assurance Committee.
Genet Med 2014 Jan;16(1):101-16. Epub 2013 Dec 5 doi: 10.1038/gim.2013.166. PMID: 24310308
Green RC, Berg JS, Grody WW, Kalia SS, Korf BR, Martin CL, McGuire AL, Nussbaum RL, O'Daniel JM, Ormond KE, Rehm HL, Watson MS, Williams MS, Biesecker LG; American College of Medical Genetics and Genomics.
Genet Med 2013 Jul;15(7):565-74. Epub 2013 Jun 20 doi: 10.1038/gim.2013.73. PMID: 23788249Free PMC Article
Aretz S, Vasen HF, Olschwang S
Eur J Hum Genet 2011 Jul;19(7) Epub 2011 Feb 2 doi: 10.1038/ejhg.2011.7. PMID: 21368914Free PMC Article
Trepanier A, Ahrens M, McKinnon W, Peters J, Stopfer J, Grumet SC, Manley S, Culver JO, Acton R, Larsen-Haidle J, Correia LA, Bennett R, Pettersen B, Ferlita TD, Costalas JW, Hunt K, Donlon S, Skrzynia C, Farrell C, Callif-Daley F, Vockley CW; National Society of Genetic Counselors.
J Genet Couns 2004 Apr;13(2):83-114. doi: 10.1023/B:JOGC.0000018821.48330.77. PMID: 15604628
Church J, Lowry A, Simmang C; Standards Task Force.; American Society of Colon and Rectal Surgeons.
Dis Colon Rectum 2001 Oct;44(10):1404-12. PMID: 11598466


Recommendations for reporting of secondary findings in clinical exome and genome sequencing, 2016 update (ACMG SF v2.0): a policy statement of the American College of Medical Genetics and Genomics.

Recent clinical studies


Silva-Velazco J, Hull TL, Stocchi L, Gorgun E
Dis Colon Rectum 2015 Mar;58(3):328-32. doi: 10.1097/DCR.0000000000000264. PMID: 25664711
Geisler D, Garrett T
Tech Coloproctol 2011 Dec;15(4):397-401. Epub 2011 Sep 2 doi: 10.1007/s10151-011-0756-7. PMID: 21887555
Aaltonen L, Johns L, Järvinen H, Mecklin JP, Houlston R
Clin Cancer Res 2007 Jan 1;13(1):356-61. doi: 10.1158/1078-0432.CCR-06-1256. PMID: 17200375


Silva-Velazco J, Hull TL, Stocchi L, Gorgun E
Dis Colon Rectum 2015 Mar;58(3):328-32. doi: 10.1097/DCR.0000000000000264. PMID: 25664711
Geisler D, Garrett T
Tech Coloproctol 2011 Dec;15(4):397-401. Epub 2011 Sep 2 doi: 10.1007/s10151-011-0756-7. PMID: 21887555
Aaltonen L, Johns L, Järvinen H, Mecklin JP, Houlston R
Clin Cancer Res 2007 Jan 1;13(1):356-61. doi: 10.1158/1078-0432.CCR-06-1256. PMID: 17200375


Silva-Velazco J, Hull TL, Stocchi L, Gorgun E
Dis Colon Rectum 2015 Mar;58(3):328-32. doi: 10.1097/DCR.0000000000000264. PMID: 25664711


Geisler D, Garrett T
Tech Coloproctol 2011 Dec;15(4):397-401. Epub 2011 Sep 2 doi: 10.1007/s10151-011-0756-7. PMID: 21887555

Clinical prediction guides

Scappaticci S, Fossati GS, Valenti L, Scabini M, Tateo S, Nastasi G, Spina MP, Capra E
Cancer Genet Cytogenet 1995 Jul 1;82(1):50-3. PMID: 7627934

Supplemental Content

Recent activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...
Support Center