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

Attenuated familial adenomatous polyposis


Other Names:
Attenuated FAP; AFAP; Mild form of FAP; Attenuated FAP; AFAP; Mild form of FAP; Attenuated familial polyposis coli; Attenuated adenomatous polyposis coli; AAPC See More
Attenuated familial adenomatous polyposis (AFAP) is an inherited condition that increases the chance to develop cancer of the large intestine (colon) and rectum. It is a milder form of classic familial adenomatous polyposis (FAP) and is characterized by fewer colon polyps (an average of 30) and a delay in the development of colon cancer (average age 50 to 55 years). Other signs and symptoms may include benign or malignant tumors of the duodenum (a section of the small intestine) and, in rare cases, other symptoms of FAP. AFAP is caused by mutations in the APC gene and is inherited in an autosomal dominant manner. AFAP is generally managed with regular screening to detect if and when polyps develop.[1]
Last updated: 4/6/2015

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
Colorectal polyposis 0200063
30%-79% of people have these symptoms
Colon cancer 0003003
Duodenal polyposis 0004783
Multiple gastric polyps 0004394
Neoplasm of the stomach
Stomach tumor
0006753
Rectal polyposis 0100896
5%-29% of people have these symptoms
Adenocarcinoma of the colon 0040276
Astrocytoma 0009592
Carious teeth
Dental cavities
Tooth cavities
Tooth decay
[ more ] 		0000670
Congenital hypertrophy of retinal pigment epithelium 0007649
Epidermoid cyst
Skin cyst
0200040
Fibroadenoma of the breast 0010619
Fibroma 0010614
Increased number of teeth
Extra teeth
Increased tooth count
Supplemental teeth
[ more ] 		0011069
Multiple renal cysts
Multiple kidney cysts
0005562
Osteoma 0100246
Papilloma 0012740
Thyroid adenoma 0000854
Unerupted tooth
Failure of eruption of tooth
0000706
Uterine leiomyoma 0000131
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
Autosomal dominant inheritance 0000006
Carcinoma 0030731
Hyperpigmentation of the skin
Patchy darkened skin
0000953
Keloids 0010562
Multiple lipomas
Multiple fatty lumps
0001012
Odontoma 0011068
Small intestine carcinoid 0006722
Variable expressivity 0003828
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Last updated: 7/1/2020
Attenuated familial adenomatous polyposis (AFAP) is generally managed with regular screening to detect if and when polyps develop.[2] Screening by colonoscopy has been recommended for affected people starting at age 20 to 25 years. People with polyps may undergo polypectomy (removal of polyps) followed by continued screenings every one to three years, depending on the number of polyps.[1] A prophylactic colectomy (removal of all or part of the colon) may be considered in people with too many adenomas to remove or those who cannot undergo screening.[3] About one third of people with AFAP have few enough colon polyps that screening with periodic polypectomy is sufficient.[1]

Because individuals with AFAP can also develop duodenal adenomas and other cancers, upper endoscopy is typically recommended starting at age 20 to 30 years and then every one to three years, depending on the number of polyps. There is currently no consensus on screening for tumors that occur outside of the colon, so it has been suggested that affected individuals are managed as if they have classic FAP.[3]

A number of drugs such as celecoxib and sulindac reportedly have been successful at reducing the number and the size of polyps in affected people, but these drugs generally help to prevent further complications and are not considered adequate treatment.[2]

Additional and more detailed information about the treatment and management of FAP, including AFAP, is available on eMedicine's Web site and can be viewed by clicking here.
Last updated: 11/28/2014

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

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 Attenuated 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 Attenuated 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 Attenuated 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 Attenuated familial adenomatous polyposis. This website is maintained by the National Library of Medicine.
  • 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 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 Attenuated 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. Submit a new question

  • I had one colonoscopy with 24 adenomatous polyps and one polyp had cancer in it. I have since been diagnosed with attenuated familial adenomatous polyposis (AFAP). I am wondering when it is recommended to remove the colon. See answer

  • What is the recommended follow up or management of AFAP after the colon has been removed? The small intestine is connected to the rectum. I have had polyps in the rectum and also in the stomach since the colon was removed. How often do I need to do follow up tests to make sure nothing is growing in there? See answer


  1. 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/.
  2. Mohammad Wehbi. Familial Adenomatous Polyposis. eMedicine. September 1, 2011; http://emedicine.medscape.com/article/175377-overview. Accessed 12/16/2011.
  3. Peter A L Bonis, MD; Dennis J Ahnen, MD; Lisen Axell, MS, CGC. Familial adenomatous polyposis and MUTYH associated polyposis: Screening and management of patients and families. UpToDate. April 2014;