Genetic Testing, Interpretation, and Communication: Exploration Across Disciplines
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Date
2018-12-10
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Johns Hopkins University
Abstract
Technological advances have made possible genomic and genetic testing for a variety of diseases, warranting examination of how we think about the risks and benefits of genetic testing. As genetic tests are increasingly incorporated into both clinical and research settings, it is critical that we understand the implications of such tests for both individuals and their family members. Questions of whether, when, and how to pursue genetic testing, interpret genetic test results, and communicate those results to family members all must be considered and are explored in this dissertation.
This study has two parts: The first part focused on ethical issues raised by genetic and genomic testing. We examined whether, when, and how to pursue genetic testing by gathering opinions on current issues in genetic testing from the first cohort of people to receive presymptomatic testing for Huntington’s Disease (HD), 20-30 years ago, who have lived with the implications of that testing for decades. Additionally, longitudinal risk perception scores, clinic notes, and interview data from this cohort were analyzed to understand how individuals interpret genetic test results as well as what factors contribute to genetic risk perception. Finally, we examined whether, when, and how genetic risk information should be to communicated to minor children, through interviews with parent child pairs affected by or at-risk for either HD or hereditary cancer, along with genetic counselors. The second part of the study focused on scientific issues raised by genetic and genomic testing. We investigated the prevalence of pathogenic germline mutations in known cancer predisposition genes in patients with metastatic breast cancer who were not selected for early age of onset or family history to provide insight into whether germline testing should be performed in the setting of metastatic breast cancer, since test results can have therapeutic implications as well as implications for one’s family members.
Results of the first part of this study, which focused on ethical issues raised by genetic and genomic testing, indicate that genetic testing requires careful consideration both in terms of its availability and the testing protocol. The majority of participants reported the importance of individual autonomy in decisions about whether and when to be tested, the need for formal testing protocols, opposition to direct-to-consumer testing for HD, and returning medically actionable secondary findings. In addition, we found that many people do not interpret genetic test results in the way one would expect. With regard to communicating genetic risk information to children, our data suggested a discrepancy in the amount of information children want and the amount of information parents are giving, a need for parents to take time to process their own result before communicating with children, and a need for additional resources on how to communicate with children about genetic risk information, as well as child-specific resources on various genetic conditions. Finally, results of the second part of this study, which focused on scientific issues raised by genetic and genomic testing, demonstrate the importance of performing germline testing in cases of metastatic breast cancer and potentially other metastatic cancers as well, given the excess of pathogenic germline mutations in known cancer predisposition genes in our population of women with metastatic breast cancer compared to the general population. This data also suggests that these pathogenic germline mutations in known cancer predisposition genes may be associated with more treatment-resistant forms of disease.
In conclusion, more resources are needed for patients to fully appreciate their genetic risk and genetic test results. More resources and guidance are also needed for patients on how to communicate results to one’s family members, particularly one’s children. Genetic counselors and other health professionals need guidance on how to communicate genetic risk information to family members in order to better assist patients. Our results should also be taken into careful consideration by disease-specific advocacy organizations, such as the American Cancer Society and the Huntington’s Disease Society of America, as well as professional societies, such as the National Society of Genetic Counselors and the American College of Medical Genetics, when considering the availability of genetic testing and testing protocols. Finally, our results should be taken into consideration by health professionals in oncology, where it may be advisable to perform germline testing in the case of metastatic breast cancer, and perhaps other cancers as well, in order to better guide treatment and to advise regarding familial cancer risk.
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Keywords
Genetic Testing, Huntington's Disease, Hereditary Cancer, Germline Testing, ELSI, Bioethics, Genetic Counseling, Risk Perception, Family Communication