Familial adenomatous polyposis (FAP) is a dominantly inherited colorectal tumor
predisposition that results from germ-line mutations in the APC gene (chromosome 5q21).
FAP shows substantial phenotypic variability: classical polyposis patients develop more than
100 colorectal adenomas, whereas those with attenuated polyposis (AAPC) have fewer than
100 adenomas. A further group of individuals, so-called “multiple” adenoma patients, have a
phenotype like AAPC, with 3–99 polyps throughout the colorectum, but mostly have no …

Whole-gene APC deletions cause classical familial adenomatous polyposis, but not
attenuated polyposis or 'multiple' colorectal adenomas | CiNii Research … Whole-gene
APC deletions cause classical familial adenomatous polyposis, but not attenuated
polyposis or 'multiple' colorectal adenomas …