Abstract
Objectives: To provide DNA-based genetic counseling to family members in the direct genetic lineage of a family fulfilling phenotypical criteria for the autosomal, dominantly inherited, attenuated familial adenomatous polyp (AFAP) syndrome. This enabled highly targeted cancer risk estimation based on cancer phenotype in concert with the presence or absence of the adenomatous polyposis coli (APC) germline mutation. Management recommendations could then be fully responsive to this syndrome's natural history. Methods: Detailed family history with pathology verification of colonic polyps and cancer was performed on an extended AFAP kindred. Endoscopic gastrointestinal examinations enabled detailed knowledge of the syndrome's upper and lower gastrointestinal tract phenotype. Molecular genetic evaluation of DNA led to the identification of the APC germline mutation which co-segregated with the phenotype. Results: Forty-two members of this extended AFAP family underwent DNA testing, wherein 27 were found to harbor the APC germline mutation, thereby enabling precision in their genetic counseling. Anecdotal examples of this counseling experience, with particular attention to psychological reactions, as well as concerns about such issues as insurance and employer discrimination, have been described. Conclusions: When DNA-based testing is offered to AFAP family members, genetic counselors must compassionately consider patients' psychological concerns when providing detailed risk status and available surveillance and management programs.