Genetic Testing
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.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."
(Citation 27)
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. 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. 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."
(Citation 27)
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. 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."
(Citation 27)
(Multimedia/Image Citation 53)