Abstract 4171: Identification of individuals with colonic polyposis in a highly inbred region

Abstract

Abstract Familial adenomatous polyposis (FAP), also known as colonic polyposis, is a hereditary autosomal dominant disease, responsible for only 1% of colorectal cancer (CRC) in the population. FAP patients with a germline mutation in the APC gene have a 100% risk of developing CRC. MAP (Mutyh associated polyposis) is the polyposis associated with biallelic mutations in the MUTYH gene, and carriers are at risk of developing CRC. Few studies propose heterozygous Mutyh mutation is associated with high risk for breast cancer, but the results are conflicting. In the city Caicó, Brazil, we identified 8 non-related breast cancer patients with the same mutation c.536A>G, p.Tyr179Cys. In this region we find high frequencies of consanguineous marriages, which varied from about 9% to 32%, suggesting a direct association to genetic diseases. We hypothesize the founding mutation MUTYH_c.536A>G was established during Dutch colonization in Brazil between 1620 and 1650. For this, we are developing a population-based, case-control study of all newly diagnosed breast cancer in this city. In our group we have one oncologist, one psychologist and one geneticist. We recruited the patients (index-cases) from the archives in the Laboratory of Pathology at the Hospital Liga contra o Cancer and we invited the individuals to participate in the research. Citation Format: Tirzah Braz Petta Lajus, Ana Rafaela Timoteo. Identification of individuals with colonic polyposis in a highly inbred region [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2019; 2019 Mar 29-Apr 3; Atlanta, GA. Philadelphia (PA): AACR; Cancer Res 2019;79(13 Suppl):Abstract nr 4171.