In a large cohort of individuals who had undergone clinical genetic testing because of a personal or family history of polyposis, 58% (851/1457) of those with classic polyposis and 9% (376/4223) of those with AFAP had APC mutations by exon-specific sequencing and large rearrangement analysis of the APC gene [3]. Here, APC is linked to attenuated familial adenomatous polyposis.