Ethical Issues in Genetic Testing

Why Genetic Testing May Lead to Ethical Dilemmas

Discussions about ethics are important in many aspects of health care but are especially critical when the health care includes genetic testing. There are several aspects of genetic testing that may lead to ethical dilemmas (e.g., the limitations of what genetic testing can provide in specific clinical situations).

Limitations of Genetic Testing

Genetic testing creates important opportunities for assessment of genetic risk and diagnosis. However, some genetic tests do not identify all of the possible gene mutations that can cause a particular condition, or they have limited predictive value.^[17] Because some genetic tests may not provide all the information that families may want, the test may subsequently require difficult decisions without providing full information. This can lead to uncertainties for patients and clinicians. As an example, CF carrier testing can identify couples who are both carriers. When the CF mutations are identified in the parents, prenatal diagnosis can be performed to determine whether a fetus has inherited a CF gene mutation from each parent. Knowing that a fetus has inherited 2 CF mutations, however, does not, at this time, predict the severity of CF in the baby. For couples in this situation, the ethical dilemma involves the decision to continue or to end a pregnancy without having knowledge of the severity of the disorder.

Should the Information Be Obtained if No Treatment or Intervention Exists?

Genetic testing can lead to specific treatments or interventions for some conditions but not for others. This is the case with some disorders that can be detected in expanded newborn screening. When phenylketonuria (PKU) is identified, dietary intervention allows individuals with this condition to lead healthy and productive lives. A new type of newborn screening technology called tandem mass spectrometry can detect more than 20 different genetic conditions.^[18] (See article by Kenner on page 219.) At present, however, not all of the conditions can be adequately treated. Although testing for these disorders can help parents and clinicians avoid "diagnostic odysseys" with an ill child, there remains no specific cure, and long-term prognosis for some patients is uncertain.^[19] Therefore, one dilemma that occurs is whether a newborn should be tested for disorders that we cannot treat? Another concern with the use of tandem mass spectrometry for newborn screening is the possibility that the screening tests can be inaccurate. A normal newborn screening result using tandem mass spectrometry does not rule out the possibility of an inborn error of metabolism in an infant with acute illness, developmental issues, or other clinically suggestive conditions.^[18]

Undesired Options After Genetic Testing

Prenatal genetic screening is commonly used to identify pregnancies at high risk for birth defects, including neural tube defects and genetic conditions such as Down syndrome. In contrast to other medical screening tests, such as blood pressure screening or testing for anemia, genetic testing in prenatal patients is focused on individual reproductive decision making rather than the management of clinical disease. A positive prenatal screening result leads to recommendations for more definitive tests to verify if a given condition is present in the fetus. For many of the conditions, there may be no treatment available before birth. Thus, a positive prenatal test result creates additional decisions for women and couples, including consideration of invasive testing, such as amniocentesis, and the possibility of pregnancy termination.^[20] This may cause an ethical dilemma for the couple, who may not want to make such decisions and may choose not to pursue prenatal screening at all. For the provider, the patient's choice not to pursue prenatal screening may cause concern due to the possibility of the birth of a baby with an unexpected birth defect.

False-Positive and False-Negative Results

Because some genetic tests are screening tests, some (e.g., the multiple marker blood test) will generate some false-positive and false-negative results. The purpose of multiple marker screening is to identify pregnant women whose fetus is at increased risk for open neural tube defects and chromosomal differences, such as Trisomy 21. Multiple marker screening detects about 80% of pregnancies in which an open neural tube defect is present and about 60% of pregnancies in which Down syndrome is present.^[21] Most women who receive false-positive results have normal pregnancy outcomes; however, these results often lead to further diagnostic testing, leading to increased anxiety about possible outcomes including pregnancy termination. A woman who receives a negative multiple marker screening result still has a residual risk for having a baby born with Down syndrome or a neural tube defect. This means that a woman who is screen negative may have, in fact, a false-negative result and have a baby born with, for example, Down syndrome.

Uncertain Implications for Early Intervention

Another growing clinical application of genetic testing is identification of the genetic contribution to risk for common diseases to guide early intervention and preventive care. Genetic testing for mutations in genes associated with hereditary breast/ovarian cancer is an example of a genetic test that can identify individuals who would benefit from individualized screening and prevention protocols based on their genetic susceptibility to breast and ovarian cancer. The estimated lifetime risk for breast cancer associated with the BRCA1 and BRCA2 mutations is in the range of 26% to 85%, and the risk of ovarian cancer is also increased.^[22] Thus, genetic testing predicts increased risk, rather than certainty of disease, making decisions about interventions, such as prophylactic mastectomy or oophorectomy, more difficult for individuals at risk.^[23] Thus, in this situation, the test may lead to decisions that cannot be reversed and are based on a woman's best guess as to what would be the best course of action for her. Removal of breast or ovarian tissue, based on a genetic test that is not diagnostic, may be regarded as meeting the goals of doing good and avoiding harm.

Potential Adverse Personal or Societal Consequences

Genetic testing for some conditions for which there are no treatments to date has the potential to cause psychological harm, stigmatization, and discrimination. Genetic testing for Huntington's disease (HD), a progressive motor and cognitive disorder with onset in midlife, is one example. Individuals who have an affected parent have a 50% chance of inheriting the gene mutation for HD and have the option to pursue genetic testing.^[24] A person who has the HD mutation has a 100% chance of developing the disease. There are no effective treatments or preventive measures currently available. Thus, choosing to have genetic testing for HD is highly personal, and it is recommended that individuals considering HD testing have extensive pretest counseling. Although knowledge that one has the HD gene mutation helps some individuals with reproductive and career planning, other individuals at risk for HD are concerned about the psychological and potential discriminatory harms from testing.

Jill is a 24-year-old woman, who provides her family history to the midwife on her first prenatal visit. Jill's father, his two brothers, and Jill's paternal grandmother have all been diagnosed with HD. In the discussion about this family history, the midwife asks Jill if she has considered the option of genetic testing to determine if she has inherited the gene mutation for this disorder. The midwife also asks if she is concerned about the possibility that her baby could be at risk to develop HD. Jill indicates that she knows that there is a lot of research going on to find a cure and that she believes something will be developed that will help her father to recover. She also does not want to have any testing, as she has read about people who have experienced discrimination in their jobs after they had the test. She tells the midwife that she does not want to have any testing for herself or her baby.

In addition to the risk for psychological harm, the test information may be used to limit the person's access to rights and privileges such as insurance or employment. Genetic discrimination occurs when an individual or an organization treats a person differently because of real or perceived genetic difference. The nature and extent of genetic discrimination are not known. Persons who qualify for genetic testing may believe it is more difficult to obtain insurance because of the testing or are afraid to change jobs because of fear of losing health insurance.^[24] Some persons at risk for HD have been reluctant to discuss genetic testing with their health care provider because of fears that this information may be revealed to their health insurance carrier.^[25] Maintenance of confidentiality of individual medical information is essential, but it may not be sufficient to eliminate the risk of discrimination against persons who have a positive result on a genetic test.

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