Nonetheless, it is important to consider the implications of testing decisions with regard to issues of informed consent for both children and their parents. Parents have the legal authority to make medical decisions on behalf of their children; however, there are justifications for increasing minors' involvement in decision-making about genetic testing as they mature and become more capable of making decisions about their own welfare.
Studies conducted before the clinical availability of APC testing showed that most parents favored testing for FAP in early childhood. In one study, 94% of FAP-affected adults indicated that children should be tested for FAP at birth, though 79% stated that this condition should not be discussed with children until at least age 10 years. The majority of respondents wished to withhold information about FAP risk from their child for nearly a decade, suggesting that research is needed regarding the timing of disclosure of cancer genetic risk information to children.
In a survey conducted in the Netherlands of members of families with FAP, one-third (34%) believed that it was most suitable to offer APC gene testing of children prior to age 12 years, whereas 38% preferred to offer testing to children between the ages of 12 and 16 years, when children would be better able to understand the DNA testing process. Only 4% felt that children should not undergo DNA testing at all.
Results of qualitative interview data from 28 U.S. parents diagnosed with FAP showed that 61% favored genetic testing of APC mutations in their at-risk children (aged 10-17 years); 71% believed that their children should receive their test results. The primary reasons why parents chose to test their children included early detection and management, reduction in parental anxiety and uncertainty, and help with decision making regarding surveillance. Reasons provided for not testing focused on discrimination concerns and cost.
Interest in the use of assisted reproductive technology (ART)
The possibility of transmitting a mutation to a child may pose a concern to families affected by hereditary colorectal cancer syndromes to the extent that some carriers may avoid childbearing. These concerns also may prompt individuals to consider using prenatal diagnosis methods to help reduce the risk of transmission. Prenatal diagnosis is an encompassing term used to refer to any medical procedure conducted to assess the presence of a genetic disorder in a fetus. Methods include amniocentesis and chorionic villous sampling .[22,23] Both procedures carry a small risk of miscarriage.[22,24] Moreover, discovering the fetus is a carrier of a cancer susceptibility mutation may impose a difficult decision for couples regarding pregnancy continuation or termination and may require additional professional consultation and support.
An alternative to these tests is preimplantation genetic diagnosis (PGD), a procedure used to test fertilized embryos for genetic disorders prior to uterine implantation.[25,26] Using the information obtained from the genetic testing, potential parents can decide whether or not to implant. PGD can be used to detect mutations in hereditary cancer predisposing genes, including APC.[20,27,28]