Familial Adenomatous Polyposis 3, also known as fap3, is related to hereditary mixed polyposis syndrome and mismatch repair cancer syndrome. An important gene associated with Familial Adenomatous Polyposis 3 is NTHL1 (Nth Like DNA Glycosylase 1). Affiliated tissues include colon and breast, and related phenotypes are adenomatous colonic polyposis and neoplasm of the skin