As part of their ongoing effort to assure that their practice is ethical, the genetics community has developed guidelines that are specifically relevant to predictive testing of children for adultonset genetic conditions. In what follows, I shall discuss the recommendations that have been advanced for withholding testing, to determine whether these policies actually conform to their foundational principles. The testing policies that I am particularly concerned with in this discussion relate to genetic conditions for which there is no phenotypic evidence for disease at the time of testing (i.e., no signs or symptoms of disease). I shall not be discussing tests that yield ambiguous results, but rather those tests the results of which may indicate a high chance of developing the condition in the future. And I will only consider tests for conditions for which, currently, there is no treatment available to prevent or forestall the development of the condition. In other words, I shall be discussing policies relevant to predictive testing for serious familial conditions in which the family history makes it clear that the child has a very significant chance of developing the disease. I have in mind the testing of asymptomatic children for conditions such as:
- Huntington’s disease (HD) (an inherited degenerative brain disorder associated with symptom onset and death in early adulthood). When one parent has the disease, a child has a 50% chance of inheriting the affected gene and developing the condition.
- Polycystic kidney disease (an inherited kidney disorder associated with kidney failure). When one parent has the disease, a child has a 50% chance of inheriting the affected gene and developing the condition.
- Familial adenomatous polyposis coli (an inherited disorder of the bowel associated with a very high incidence of early onset bowel cancer). When one parent has the disease, a child has a 50% chance of inheriting the affected gene and developing the condition.
- Early-onset Alzheimer’s disease (an inherited degenerative brain disorder associated with symptom onset and death in early adulthood). When one parent has the disease, a child has an approximately 50% chance of inheriting the affected gene and developing the condition.
- Early-onset breast or ovarian cancer (an inherited disposition to develop breast or ovarian cancer in early adulthood). When one parent has the disease, a child has approximately a 25 – 30% chance of developing the condition.
- Dominant variant of Charcot-Marie- Tooth disease (an inherited degenerative nerve disorder). When one parent has the disease, a child has approximately a 50% chance of inheriting the affected gene and developing the condition.
Members of the genetics community have expressed their aversion to predictive testing of children for such adult-onset genetic diseases, and in the early 1990s they issued position statements that strongly advised against predictive testing of children for genetic diseases that begin in adulthood (1 – 3). These position statements do, however, acknowledge that there might be a very few “clear-cut and exceptional circumstances” that could justify testing in a particular case. Genetics policy makers have offered three reasons to justify their restriction of predictive testing of children for adult onset genetic conditions. (a) They maintain that restricting predictive testing of children for adult-onset genetic conditions is respectful of autonomy and confidentiality because the decision is left to the patient, who will be able to decide when he or she becomes autonomous years down the road. By refusing to perform the test when an immature child and/or the parents request testing of the minor, the geneticist is preserving the decision for the future mature patient. Because the child is not tested now, the grown patient will be able to make the decision about whether or not to be tested and who should have access to the test results (4 – 6). (b) Geneticists also argue that the tests are harmful in that they carry a significant risk of the “unbearable certainty of knowing,” damage to selfesteem, survivor guilt, and injury to the family dynamics. (c) Furthermore, as they see it, these harms are not offset by any benefits, because no effective treatment is available.
Starting in the late 1990s, policy makers and other authors who discuss this matter in the literature have taken remarkably similar positions that differ only slightly from the earlier stand of the genetics community. In fact, those recently writing on this issue have been so consistent in these views that we can count their conclusions as representing an emerging consensus (7 – 11). In their articles, Cohen (5), as well as Robertson and Savulescu (6), make several telling points. They note that the same hypothetical considerations can result in harms or benefits, that parental authority is an additional important consideration, and that hypothetical harmful outcomes are neither likely enough nor serious enough to justify overriding parental authority. Nevertheless, Cohen, as well as Robertson and Savulescu, conclude that geneticists should only comply with parental requests to test mature children (12 – 14 years old) who have demonstrated understanding of the tests and their implications and who also want the information (i.e., assent to testing).
What is now commonly recommended is that a decision on testing by the geneticist should be based on the facts of the particular case. In response to a request for testing a minor, and before agreeing to provide the test, a geneticist should begin with an assessment of the minor’s competence to make the testing decision for her/himself, compare the benefits and harms of testing, and use that information in deciding whether the testing should be performed. The popularity of this reigning view among clinicians is documented in a report on an international survey conducted by Rony Duncan and colleagues that is described in a 2005 publication in Genetics in Medicine (12). Although this approach seems reasonable on its face, I shall be arguing that this consensus position is not justified.
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