Familial Adenomatous Polyposis
Clinical
- Genetic counseling should be offered before genetic testing is performed
- Autosomal dominant with 100% penetrance
- Attenuated FAP may be <100%
- 25% of cases have no family history and represent de novo germline mutations
- Recognition of associated lesions, especially in children should lead to consideration of FAP
- Colorectal polyps appear generally between 10-20 years of age
- Mean age of carcinoma is 40 years
- Mean age 55 years in attenuated FAP
- Colectomy with constant surveillance of rectum or complete proctocolectomy removes the threat of colorectal carcinoma
- Extra-colorectal neoplasms may still occur
- Screening
- If APC mutation is identified in index case, screen positive family members starting at age 10
- If mutation not identified in the index case, screen all family members from age 10 through 40
- Attenuated FAP families should continue screening past 40
- All patients diagnosed with FAP require upper GI screening
