Mutations in APC can lead to both classic (FAP) and attenuated familial adenomatous polyposis (AFAP), while mutations in MUTYH (biallelic) can lead to MUTYH-associated polyposis (MAP), mutations in NTHL1 (biallelic) can lead to familial adenomatous polyposis 3 (FAP3), and mutations in POLE and POLD1 can lead to Polymerase proofreading-associated polyposis (PPAP) [4–7]. Here, NTHL1 is linked to mutyh-associated polyposis.