National Center for Advancing and Translational Sciences Genetic and Rare Diseases Information Center, a program of the National Center for Advancing and Translational Sciences

Familial adenomatous polyposis


Other Names:
Adenomatous polyposis coli; FAP; Familial adenomatous polyposis of the colon; Adenomatous polyposis coli; FAP; Familial adenomatous polyposis of the colon; Familial polyposis of the colon; Polyposis, adenomatous intestinal; FPC; Adenomatous polyposis of the colon; Familial intestinal polyposis; Familial multiple polyposis; Hereditary polyposis coli; Familial polyposis coli See More
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Subtypes:
Familial adenomatous polyposis (FAP) is an inherited condition that causes cancer of the large intestine (colon) and rectum. People with the classic type of FAP usually develop hundreds to thousands of noncancerous (benign) polyps (growths) in the colon as early as their teenage years. Overtime, these polyps can become malignant (cancerous), leading to early-onset colorectal cancer at an average age of 39 years.[1] Other signs and symptoms may include dental abnormalities; desmoid tumors; and benign and malignant tumors of the duodenum (a section of the small intestine), stomach, bones, skin, and other tissues.[2] Some people have a milder form of the condition called attenuated familial adenomatous polyposis (AFAP) which is generally characterized by fewer colon polyps (an average of 30) and a delay in the development of colon cancer by 10-15 years.[1] FAP is caused by changes (mutations) in the APC gene and is inherited in an autosomal dominant manner. People with FAP usually undergo regular screening until they develop 20 to 30 polyps and then a colectomy (removal of colon) is generally recommended.[2]
Last updated: 11/26/2014
The signs and symptoms of familial adenomatous polyposis (FAP) vary both within families and between families. Classic FAP is characterized primarily by hundreds to thousands of noncancerous (benign) polyps (growths) in the colon that begin to appear at an average age of 16 years. Unless the colon is removed, these polyps will become malignant (cancerous), leading to early-onset colorectal cancer at an average age of 39 years.[1][2]

Other features of FAP may include:[2]
  • Fundic gland or adenomatous polyps of the stomach
  • Adenomatous polyps of the small intestines
  • Osteomas (benign bone tumors)
  • Dental abnormalities
  • Congenital hypertrophy of the retinal pigment epithelium (a flat, pigmented spot within the outer layer of the retina)
  • Benign skin abnormalities
  • Adrenal masses
  • Desmoid tumors
  • Other types of cancer (small bowel, stomach, pancreas, thyroid, central nervous system, liver, bile ducts, and/or adrenal gland)
Last updated: 11/26/2014

This table lists symptoms that people with this disease may have. For most diseases, symptoms will vary from person to person. People with the same disease may not have all the symptoms listed. This information comes from a database called the Human Phenotype Ontology (HPO) . The HPO collects information on symptoms that have been described in medical resources. The HPO is updated regularly. Use the HPO ID to access more in-depth information about a symptom.

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Medical Terms Other Names
Learn More:
HPO ID
80%-99% of people have these symptoms
Adenomatous colonic polyposis 0005227
Duodenal polyposis 0004783
Multiple gastric polyps 0004394
30%-79% of people have these symptoms
Colon cancer 0003003
5%-29% of people have these symptoms
Carious teeth
Dental cavities
Tooth cavities
Tooth decay
[ more ] 		0000670
Congenital hypertrophy of retinal pigment epithelium 0007649
Delayed eruption of teeth
Delayed eruption
Delayed teeth eruption
Delayed tooth eruption
Eruption, delayed
Late eruption of teeth
Late tooth eruption
[ more ] 		0000684
Epidermoid cyst
Skin cyst
0200040
Fibroadenoma of the breast 0010619
Fibroma 0010614
Increased number of teeth
Supplemental teeth
Extra teeth
Increased tooth count
[ more ] 		0011069
Irregular hyperpigmentation 0007400
Multiple lipomas
Multiple fatty lumps
0001012
Neoplasm of the central nervous system
Tumors of the central nervous system
0100006
Odontoma 0011068
Osteoma 0100246
Unerupted tooth
Failure of eruption of tooth
0000706
1%-4% of people have these symptoms
Adrenocortical adenoma 0008256
Desmoid tumors 0100245
Duodenal adenocarcinoma 0006771
Hepatoblastoma 0002884
Medulloblastoma 0002885
Papillary thyroid carcinoma 0002895
Percent of people who have these symptoms is not available through HPO
Adrenocortical carcinoma 0006744
Astrocytoma 0009592
Autosomal dominant inheritance 0000006
Carcinoma 0030731
Hyperpigmentation of the skin
Patchy darkened skin
0000953
Keloids 0010562
Small intestine carcinoid 0006722
Variable expressivity 0003828
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Last updated: 7/1/2020
Genetic testing is available for the gene known to cause familial adenomatous polyposis (FAP). Prenatal testing and genetic testing for at-risk relatives are possible if the disease-causing mutation in the family is known. Because colon screening for those at risk for classic FAP begins as early as age ten years, genetic testing is generally offered to children by this age. Testing may be offered earlier if the child is showing signs or symptoms of FAP.[2]

The Genetic Testing Registry (GTR) is a centralized online resource for information about genetic tests. The intended audience for the GTR is health care providers and researchers. Patients and consumers with specific questions about a genetic test should contact a health care provider or a genetics professional.
Last updated: 11/26/2014

If you need medical advice, you can look for doctors or other healthcare professionals who have experience with this disease. You may find these specialists through advocacy organizations, clinical trials, or articles published in medical journals. You may also want to contact a university or tertiary medical center in your area, because these centers tend to see more complex cases and have the latest technology and treatments.

If you can’t find a specialist in your local area, try contacting national or international specialists. They may be able to refer you to someone they know through conferences or research efforts. Some specialists may be willing to consult with you or your local doctors over the phone or by email if you can't travel to them for care.

You can find more tips in our guide, How to Find a Disease Specialist. We also encourage you to explore the rest of this page to find resources that can help you find specialists.

Healthcare Resources

Related diseases are conditions that have similar signs and symptoms. A health care provider may consider these conditions in the table below when making a diagnosis. Please note that the table may not include all the possible conditions related to this disease.

Conditions with similar signs and symptoms from Orphanet
Differential diagnoses include other disorders causing multiple polyps (Peutz-Jeghers syndrome, familial juvenile polyposis or hyperplastic polyposis, hereditary mixed polyposis syndrome, and Lynch syndrome; see these terms).
Visit the Orphanet disease page for more information.

Research helps us better understand diseases and can lead to advances in diagnosis and treatment. This section provides resources to help you learn about medical research and ways to get involved.

Clinical Research Resources

  • ClinicalTrials.gov lists trials that are related to Familial adenomatous polyposis. Click on the link to go to ClinicalTrials.gov to read descriptions of these studies.

    Please note: Studies listed on the ClinicalTrials.gov website are listed for informational purposes only; being listed does not reflect an endorsement by GARD or the NIH. We strongly recommend that you talk with a trusted healthcare provider before choosing to participate in any clinical study.

Patient Registry

  • A registry supports research by collecting of information about patients that share something in common, such as being diagnosed with Familial adenomatous polyposis. The type of data collected can vary from registry to registry and is based on the goals and purpose of that registry. Some registries collect contact information while others collect more detailed medical information. Learn more about registries.

    Registries for Familial adenomatous polyposis:
    DTRF Desmoid Tumor Patient Registry
     

Support and advocacy groups can help you connect with other patients and families, and they can provide valuable services. Many develop patient-centered information and are the driving force behind research for better treatments and possible cures. They can direct you to research, resources, and services. Many organizations also have experts who serve as medical advisors or provide lists of doctors/clinics. Visit the group’s website or contact them to learn about the services they offer. Inclusion on this list is not an endorsement by GARD.

Organizations Supporting this Disease

Organizations Providing General Support

These resources provide more information about this condition or associated symptoms. The in-depth resources contain medical and scientific language that may be hard to understand. You may want to review these resources with a medical professional.

Where to Start

  • Genetics Home Reference (GHR) contains information on Familial adenomatous polyposis. This website is maintained by the National Library of Medicine.
  • The Merck Manual provides information on this condition for patients and caregivers. 
  • The National Cancer Institute provides the most current information on cancer for patients, health professionals, and the general public.
  • The National Organization for Rare Disorders (NORD) has a report for patients and families about this condition. NORD is a patient advocacy organization for individuals with rare diseases and the organizations that serve them.

In-Depth Information

  • GeneReviews provides current, expert-authored, peer-reviewed, full-text articles describing the application of genetic testing to the diagnosis, management, and genetic counseling of patients with specific inherited conditions.
  • Medscape Reference provides information on this topic. You may need to register to view the medical textbook, but registration is free.
  • The Merck Manual for health care professionals provides information on Familial adenomatous polyposis.
  • The Monarch Initiative brings together data about this condition from humans and other species to help physicians and biomedical researchers. Monarch’s tools are designed to make it easier to compare the signs and symptoms (phenotypes) of different diseases and discover common features. This initiative is a collaboration between several academic institutions across the world and is funded by the National Institutes of Health. Visit the website to explore the biology of this condition.
  • Online Mendelian Inheritance in Man (OMIM) is a catalog of human genes and genetic disorders. Each entry has a summary of related medical articles. It is meant for health care professionals and researchers. OMIM is maintained by Johns Hopkins University School of Medicine. 
  • Orphanet is a European reference portal for information on rare diseases and orphan drugs. Access to this database is free of charge.
  • PubMed is a searchable database of medical literature and lists journal articles that discuss Familial adenomatous polyposis. Click on the link to view a sample search on this topic.

Questions sent to GARD may be posted here if the information could be helpful to others. We remove all identifying information when posting a question to protect your privacy. If you do not want your question posted, please let us know.

  1. Familial Adenomatous Polyposis. Genetic Home Reference. October 2013; http://www.ghr.nlm.nih.gov/condition/familial-adenomatous-polyposis.
  2. Kory W Jasperson, MS and Randall W Burt, MD. APC-Associated Polyposis Conditions. GeneReviews. March 27, 2014; http://www.ncbi.nlm.nih.gov/books/NBK1345/.