Attenuated familial adenomatous polyposis: an evolving and poorly understood entity
Diseases of the Colon and Rectum
|January 12, 2002
Summary
Attenuated familial adenomatous polyposis (AFAP) presents with fewer polyps and later onset than classic FAP. Awareness and specific guidelines are crucial for improved diagnosis and management of this distinct inherited colorectal cancer syndrome.
Area of Science:
- Gastroenterology
- Genetics
- Oncology
Background:
- Familial adenomatous polyposis (FAP) is an autosomal dominant syndrome with diffuse colorectal polyposis.
- Attenuated FAP (AFAP) is a variant with fewer polyps, later onset, and proximal colon predilection.
- AFAP presents unique diagnostic and management challenges due to its distinct characteristics.
Purpose of the Study:
- To review current knowledge on attenuated familial adenomatous polyposis.
- To propose guidelines for diagnosis, surveillance, and surgical management of AFAP.
- To enhance understanding of this poorly understood FAP variant.
Main Methods:
- MEDLINE database search from 1985 onward.
- Keywords included "attenuated familial adenomatous polyposis," "AFAP," and "APC gene."
- Included articles on AFAP and APC gene mutations causing an attenuated phenotype.
Main Results:
- AFAP is autosomal dominant, linked to distinct APC gene mutations.
- Disease expression varies even within families with identical mutations.
- Polyps diagnosed at mean age 44, cancer at mean 56; proximal colon involvement is common.
Conclusions:
- AFAP may represent a spectrum of FAP caused by different APC mutations.
- Its characteristics overlap with FAP and hereditary nonpolyposis colorectal cancer.
- Increased awareness of AFAP is needed to improve diagnosis, surveillance, and treatment.
