Attenuated familial adenomatous polyposis (AFAP) a phenotypically and genotypically distinctive variant of FAP

Abstract

AFAP is a phenotypically distinctive syndrome, differing from classic FAP by having fewer colonic adenomas that tend to be proximally distributed and flat rather than polypoid. The position of the APC germline mutation appears to allow for the molecular differentiation between FAP and the attenuated variant in that the extreme 5' APC mutations are associated with the latter.