90 15.10 Ethics of Genetic Testing and Medical Disease Diagnostics
Jung Choi; Mary Ann Clark; and Matthew Douglas
Traditionally, disease is diagnosed when a patient suffers from symptoms or measurable signs. Some diseases are caused (at least in part) by genetic changes to a single gene, some by genetic changes to multiple genes, some by changes to chromosomes or their interactions with the environment. Sickle cell anemia, cystic fibrosis, some versions of hemophilia, phenylketonuria, and Huntington’s disease are caused by mutations to a specific gene or location on a chromosome. Some diseases such as a type 2 diabetes are thought to be influenced by many genes and environmental factors. Some diseases such as trisomy 21 (also known as Down syndrome) are caused when an additional third chromosome is part of someone’s genetic information. Some diseases have a genetic component that increases the risk for a disease, but does not determine with 100% certainty that a person will develop that disease. An example are some mutations in BRCA1 that can increase the risk for breast cancer. Some diseases caused by genetic mutations are life-ending at an early age. Examples are mutations for the gene encoding ADA. ADA is an abbreviation for adenosine deaminase. A mutation causing lack of ADA can cause “severe combined immunodeficiency” (SCID). Persons with non-functional ADA die at a very young age (a few years old) from the lack of a functional immune system, overcome by infections turning lethal against them. Some genetic diseases such as phenylketonuria (PKU) can lead to impairing the cognitive development of a person without intervention. On the other hand, mental impairment can be avoided by giving a diet that avoids or strongly reduces the amount of phenylalanine. Some diseases with genetic components such as diabetes can be improved with improving diets, exercises, patient education, and life style changes. Other genetic diseases such as breast cancer can be monitored with routine testing. Some genetic diseases such as Huntington’s disease are fatal but often start to show the signs and symptoms of illness only later in life, oftentimes when someone is in their 30s or 40s. Some genetic diseases can’t be cured (as of yet but perhaps in the future). Unfortunately, Huntington’s disease is one example. For some genetic diseases, a person can have a recessive disease-causing allele for a gene on one paternal chromosome and a normal allele for the same gene on the chromosome from the other parent. When individuals in this genetic situation have biological children, then there is a chance that one of the children will inherit disease-causing alleles from both parents and suffer from the genetic disease. Sickle cell disease is an example of this type of genetic situation.
In 2005, the National Society of Genetic Counselors (NSGC) defined genetic counseling as “the process of helping people understand and adapt to the medical, psychological and familial implications of genetic contributions to disease” (Waxler, JL 2012). The World Health Organization (WHO) is also developing and presenting some ethical framework for genetic diseases and genetic testing (Ethical aspects of early diagnosis of genetic diseases. Kare Berg. World Health. No 9. 1996; Control of genetic diseases. Report by the Secretariat. World Health Organization. Executive Board. 116th Session. Provisional Agenda item 4.1. 21 April 2005). The WHO has guidelines for the “best possible treatment and prevention.” The WHO promotes also the autonomy of the individual and the right to full information about the genetic disease and available options. It also promotes that genetic counseling should be educational, voluntary, and non-prescriptive. It should also be sensitive to the societal, cultural, and religious views of the individual. Besides the “right to know,” the question about “the right not to know” arises. Do physicians have a duty to share the information about a risk with a patient who doesn’t want to know or a family member who might be at risk and is totally unaware of the risk?
Ethics questions:
- Should parents test themselves for genetic diseases or disease conditions before they decide to have children? If parents find out that their children have a risk of getting a genetic disease, should they decide against biological children? How high does the risk have be—low, moderate, high?
- The actress Angelina Jolie wrote an open opinion letter to the New York Times entitled “My Medical Choice.” The actress decided to test for an allele of the BRCA1 gene that can increase the breast cancer risk. The actress found out that she had the allele that causes increased risk for breast cancer. The actress then had her breast tissue removed (mastectomy) in order to reduce the risk for breast cancer. What do you think about her choice to take the test? What do you think about her choice to proactively have surgery? BRCA1 mutations can also increase risk for ovarian cancer. What do you think about proactively removing the ovaries? The government website from the national cancer institute has some medical information about the BRCA1 gene: http://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet#q2.
- A grandparent had Huntington’s disease. The parents don’t want to get tested. If a child wants to know their risk of Huntington’s disease, should they get tested even if the disease can’t be cured? If the kid is found to have Huntington’s disease, then their parent might have a high change of also having it. Can the parent forbid the child to get tested, as the parent doesn’t want to know about their own risk?
- Should embryos or fetuses be tested for genetic disease? What would you do as a parent if you find out your unborn child suffers from a genetic disease? Does it make a difference if the disease is severe, mild, untreatable, treatable, life-changing in the 30s or 40s like Huntington’s disease, of life-shortening like ADA SCID?
Further reading
Ethical aspects of early diagnosis of genetic diseases. Kare Berg. World Health. No 9. 1996 https://apps.who.int/iris/bitstream/handle/10665/330524/WH-1996-Sep-Oct-p20-21-eng.pdf accessed 4/18/2022; freely available via the internet
Control of genetic diseases. Report by the Secretariat. World Health Organization. Executive Board. 116th Session. Provisional Agenda item 4.1. 21 April 2005 https://apps.who.int/gb/archive/pdf_files/EB116/B116_3-en.pdf; freely available via the internet
Waxler, JL, O’Brien, KE, Delahanty, LM, Meigs, JB, Florez, JC, Park, ER, Pober, BR & Grant, RW 2012, ‘Genetic counseling as a tool for type 2 diabetes prevention: A genetic counseling framework for common polygenetic disorders’, Journal of Genetic Counseling, vol. 21, no. 5, pp. 684–691, viewed 18 April 2022,
Ellington, L., Maxwel, A., Baty, B. J., Roter, D., Dudley, W. N., & Kinney, A. Y. (2007). Genetic counseling communication with an African American BRCA1 kindred. Social Science & Medicine, 64(3), 724-734. doi:10.1016/j.socscimed.2006.09.017
My Medical Choice. By ANGELINA JOLIE. New York Times. MAY 14, 2013. http://www.nytimes.com/2013/05/14/opinion/my-medical-choice.html?_r=0
BRCA Gene Mutations: Cancer Risk and Genetic Testing. National Cancer Institute. https://www.cancer.gov/about-cancer/causes-prevention/genetics/brca-fact-sheet#q2 accessed 4/21/2022
Huntington Disease. Online Mendelian Inheritance in Man. Johns Hopkins University. Creation Date: Victor A. McKusick: 6/4/1986. Contributors: Ada Hamosh – updated: 12/06/2019 https://www.omim.org/entry/143100?search=huntington&highlight=huntington; accessed 4/18/2022. Note: OMIM is intended for use primarily by physicians and other professionals concerned with genetic disorders, by genetics researchers, and by advanced students in science and medicine. While the OMIM database is open to the public, users seeking information about a personal medical or genetic condition are urged to consult with a qualified physician for diagnosis and for answers to personal questions.
Sickle Cell Anemia. Online Mendelian Inheritance in Man. Johns Hopkins University. https://www.omim.org/entry/603903?search=%22sickle%20cell%20disease%22&highlight=%22sickle%20cell%20disease%22; accessed 4/18/2022. Note: OMIM is intended for use primarily by physicians and other professionals concerned with genetic disorders, by genetics researchers, and by advanced students in science and medicine. While the OMIM database is open to the public, users seeking information about a personal medical or genetic condition are urged to consult with a qualified physician for diagnosis and for answers to personal questions.
Cystic Fibrosis. Online Mendelian Inheritance in Man. Johns Hopkins University. https://www.omim.org/entry/219700?search=cystic%20fibrosis&highlight=cystic%20fibrosi; accessed 4/18/2022. Note: OMIM is intended for use primarily by physicians and other professionals concerned with genetic disorders, by genetics researchers, and by advanced students in science and medicine. While the OMIM database is open to the public, users seeking information about a personal medical or genetic condition are urged to consult with a qualified physician for diagnosis and for answers to personal questions.
Phenylketonuria. Online Mendelian Inheritance in Man. Johns Hopkins University. https://www.omim.org/entry/261600?search=phenylketonuria&highlight=phenylketonuria
Pre-natal diagnosis and Screening for Downsyndrome. Edited by Subrata Dey. Intech Open. https://mts.intechopen.com/storage/books/479/authors_book/authors_book.pdf; accessed 4/18/2022; Individual chapters of this publication are distributed under the terms of the Creative Commons Attribution 3.0
https://sitn.hms.harvard.edu/flash/2018/understanding-ownership-privacy-genetic-data/