Genetic testing and counseling in familial adenomatous polyposis.

Testing for adenomatous polyposis coli (APC), the gene responsible for familial adenomatous polyposis (FAP), can now be offered to family members in FAP kindreds. With the availability of this test, genetic counseling has become a crucial tool for helping FAP patients and their relatives understand the syndrome and its implications and for assisting at-risk individuals in making informed decisions about whether or not to undergo genetic testing. Genetic counseling can occur at several time points: when FAP is diagnosed, when an FAP patient is considering reproductive options, when a patient is deciding whether to have his or her children screened, and when an at-risk person is considering genetic testing. Based on our experiences from working with families in a large FAP registry, we explore the different issues that emerge in each of these settings, and how the genetic counselor or clinician can help FAP patients, family members, and at-risk persons deal with these issues.