Overview
Familial adenomatous polyposis (FAP) is a rare inherited condition that causes hundreds to thousands of small growths called polyps to form inside the large intestine (colon) and rectum. These polyps are not cancer at first, but if left untreated, they almost always turn into colorectal cancer — usually before age 40. FAP is also sometimes called adenomatous polyposis coli or classic FAP. The condition is caused by a change (mutation) in a gene called APC. Beyond the colon, FAP can also cause polyps in the stomach and small intestine, as well as non-cancerous growths in other parts of the body such as the bones, skin, and eyes. A milder form called attenuated FAP (AFAP) causes fewer polyps and a later cancer risk. Because the cancer risk is so high, most people with FAP need surgery to remove part or all of the colon. Regular monitoring and early treatment can save lives. With proper care, many people with FAP live full and meaningful lives, though lifelong medical follow-up is essential.
Key symptoms:
Hundreds or thousands of polyps (small growths) in the colon and rectumRectal bleeding or blood in the stoolDiarrhea or changes in bowel habitsStomach pain or crampingUnexplained weight lossFatigue and tirednessPolyps in the stomach or small intestineBenign (non-cancerous) bone growths called osteomasCysts under the skin (epidermoid cysts)Benign eye spots called CHRPE (congenital hypertrophy of the retinal pigment epithelium)Desmoid tumors (fibrous growths, often in the abdomen)Dental abnormalities such as extra teethIncreased risk of other cancers including thyroid, liver, and brain tumors
Autosomal dominant
Passed on from just one parent; each child has about a 50% chance of inheriting it
Juvenile
Begins in the teen years
FDA & Trial Timeline
2 eventsHonorHealth Research Institute — PHASE1, PHASE2
National Cancer Center, Japan
Data sourced from FDA regulatory filings and ClinicalTrials.gov. Updated periodically.
Treatments
No FDA-approved treatments are currently listed for Rare genetic tumor.
1 clinical trialare actively recruiting — trials can provide access to cutting-edge therapies.
View clinical trials →Rare Disease Specialist
Rare Disease Specialist
Rare Disease Specialist
Rare Disease Specialist
Rare Disease Specialist
Rare Disease Specialist
Treatment Centers
8 centersBaylor College of Medicine Rare Disease Center ↗
Baylor College of Medicine
📍 Houston, TX
🏥 NORDStanford Medicine Rare Disease Center ↗
Stanford Medicine
📍 Stanford, CA
🔬 UDNNIH Clinical Center Undiagnosed Diseases Program ↗
National Institutes of Health
📍 Bethesda, MD
🔬 UDNUCLA UDN Clinical Site ↗
UCLA Health
📍 Los Angeles, CA
🔬 UDNBaylor College of Medicine UDN Clinical Site ↗
Baylor College of Medicine
📍 Houston, TX
🔬 UDNHarvard/MGH UDN Clinical Site ↗
Massachusetts General Hospital
📍 Boston, MA
🏥 NORDMayo Clinic Center for Individualized Medicine ↗
Mayo Clinic
📍 Rochester, MN
👤 Mayo Clinic Center for Individualized Medicine
🏥 NORDUCLA Rare Disease Day Program ↗
UCLA Health
📍 Los Angeles, CA
Travel Grants
No travel grants are currently matched to Rare genetic tumor.
Community
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Start the conversation →Latest news about Rare genetic tumor
Disease timeline:
New recruiting trial: Marker Assisted Selective ThErapy in Rare Cancers: Knowledge Database Establishing registrY Asia
A new clinical trial is recruiting patients for Rare genetic tumor
Caregiver Resources
NORD Caregiver Resources
Support, advocacy, and financial assistance for caregivers of rare disease patients.
Mental Health Support
Rare disease caregiving can be isolating. Connect with counseling and peer support.
Family & Caregiver Grants
Financial assistance programs specifically for caregivers of rare disease patients.
Social Security Disability
Learn how rare disease patients may qualify for SSDI/SSI benefits.
Questions for your doctor
Bring these to your next appointment
- Q1.At what age should my child or I start having colonoscopies, and how often?,Which type of surgery is best for my situation, and when should it happen?,Should other members of my family be tested for the APC gene mutation?,What are the signs of desmoid tumors, and how would they be treated?,Are there medications that can help reduce my polyps, and are they right for me?,What other cancers should I be screened for, and how often?,Are there clinical trials or new treatments I should know about?
Common questions about Rare genetic tumor
What is Rare genetic tumor?
Familial adenomatous polyposis (FAP) is a rare inherited condition that causes hundreds to thousands of small growths called polyps to form inside the large intestine (colon) and rectum. These polyps are not cancer at first, but if left untreated, they almost always turn into colorectal cancer — usually before age 40. FAP is also sometimes called adenomatous polyposis coli or classic FAP. The condition is caused by a change (mutation) in a gene called APC. Beyond the colon, FAP can also cause polyps in the stomach and small intestine, as well as non-cancerous growths in other parts of the body
How is Rare genetic tumor inherited?
Rare genetic tumor follows a autosomal dominant inheritance pattern. Genetic counseling can help families understand recurrence risk and testing options.
At what age does Rare genetic tumor typically begin?
Typical onset of Rare genetic tumor is juvenile. Age of onset can vary across affected individuals.
Are there clinical trials for Rare genetic tumor?
Yes — 1 recruiting clinical trial is currently listed for Rare genetic tumor on UniteRare. See the clinical trials section on this page for phase, sponsor, and site details sourced from ClinicalTrials.gov.
Which specialists treat Rare genetic tumor?
24 specialists and care centers treating Rare genetic tumor are listed on UniteRare, sourced from ClinicalTrials.gov principal investigators, published research, and the NPPES NPI registry.