Attenuated familial adenomatous polyposis

Title

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

Summary Summary

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

Symptoms Symptoms

The Human Phenotype Ontology (HPO) provides the following list of features that have been reported in people with this condition. Much of the information in the HPO comes from Orphanet, a European rare disease database. If available, the list includes a rough estimate of how common a feature is (its frequency). Frequencies are based on a specific study and may not be representative of all studies. You can use the MedlinePlus Medical Dictionary for definitions of the terms below.

Signs and Symptoms	Approximate number of patients (when available)
Adenomatous colonic polyposis	Very frequent (present in 80%-99% of cases)
Colon cancer	Frequent (present in 30%-79% of cases)
Multiple gastric polyps	Frequent (present in 30%-79% of cases)
Carious teeth	Occasional (present in 5%-29% of cases)
Congenital hypertrophy of retinal pigment epithelium	Occasional (present in 5%-29% of cases)
Fibroadenoma of the breast	Occasional (present in 5%-29% of cases)
Increased number of teeth	Occasional (present in 5%-29% of cases)
Osteoma	Occasional (present in 5%-29% of cases)
Unerupted tooth	Occasional (present in 5%-29% of cases)
Adrenocortical adenoma	Very rare (present in 1%-4% of cases)
Desmoid tumors	Very rare (present in 1%-4% of cases)
Duodenal adenocarcinoma	Very rare (present in 1%-4% of cases)
Duodenal polyposis	Very rare (present in 1%-4% of cases)
Hepatoblastoma	Very rare (present in 1%-4% of cases)
Medulloblastoma	Very rare (present in 1%-4% of cases)
Papillary thyroid carcinoma	Very rare (present in 1%-4% of cases)
Adrenocortical carcinoma	-
Astrocytoma	-
Autosomal dominant inheritance	-
Hyperpigmentation of the skin	-
Keloids	-
Multiple lipomas	-
Odontoma	-
Small intestine carcinoid	-
Variable expressivity	-

Last updated: 9/1/2017

Treatment Treatment

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

Management Guidelines

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.

Do you have updated information on this condition? Let us know.

Research Research

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 studying or have studied 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.

Organizations Organizations

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

Colon Cancer Alliance
1025 Vermont Ave, NW
Suite 1066
Washington, DC 20005
Toll-free: (877) 422-2030 (Helpline)
Telephone: +1-202-628-0123 (Office)
Website: https://www.ccalliance.org/
FAP Gene Support Group
12 Freeby Close Melton Mowbray
Leicestershire , LE13 1HN United Kingdom
Telephone: 01664-566101
E-mail: enquiries@fapgene.com
Website: http://www.fapgene.com/
Fight Colorectal Cancer
134 West Park Central Square
Suite 210
Springfield, MO 65806
Toll-free: 1-877-42712111 (Helpline)
Telephone: +1-703-548-1225 (Office)
E-mail: answer@fightcrc.org
Website: http://fightcolorectalcancer.org/
Hereditary Colon Cancer Foundation
1776 Park Avenue, Suite 4-203
Suite 4-203
Park City, UT 84060
Telephone: +1-334-740-8657
E-mail: info@HCCTakesGuts.org
Website: http://www.hcctakesguts.org/

Organizations Providing General Support

American Cancer Society
250 Williams Street NW
Atlanta, GA 30329
Toll-free: 800-227-2345
Website: http://www.cancer.org

Do you know of an organization? Send us your suggestions.

Living With Living With

Living with a genetic or rare disease can impact the daily lives of patients and families. These resources can help families navigate various aspects of living with a rare disease.

Genetics Resources

To find a medical professional who specializes in genetics, you can ask your doctor for a referral or you can search for one yourself. Online directories are provided by GeneTests, the American College of Medical Genetics, and the National Society of Genetic Counselors. If you need additional help, contact a GARD Information Specialist. You can also learn more about genetic consultations from Genetics Home Reference.

Learn More Learn More

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

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.

News & Events News & Events

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GARD Answers GARD Answers

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

Have a question? Contact a GARD Information Specialist.

References References

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/.
Mohammad Wehbi. Familial Adenomatous Polyposis. eMedicine. September 1, 2011; http://emedicine.medscape.com/article/175377-overview. Accessed 12/16/2011.
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;

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