Characterization of family history profiles in a large series of Lynch syndrome carriers.

414 Background: The identification of Lynch syndrome carriers is an unmet medical need. Large studies characterizing family history profiles of unaffected individuals diagnosed with Lynch syndrome in the absence of a known family mutation have not been reported. Methods: We queried our laboratory database for unaffected patients who underwent Lynch syndrome genetic testing between September 2010 and May 2013 and had a positive test result. All individuals underwent full sequence and large rearrangement analysis of MLH1 and MSH2, and full sequence analysis of MSH6. Some patients also underwent full sequence and large rearrangement analysis of PMS2 and large rearrangement analysis of MSH6 and EPCAM. Those being tested for a known mutation in the family and patients undergoing single gene testing were excluded. We assessed family history profiles in 200 unaffected patients with genetically confirmed Lynch syndrome. Results: Of the 200 patients, 162 female and 38 male Lynch syndrome carriers were identified. ...