Genetic Testing Discussion Scenario

 

Introduction

 

Welcome to the Discussion Scenarios. The five scenarios in this section present many of the ethical issues that come up in connection with some uses of biotechnology. You've entered a discussion about: genetic testing.

You are about to read a series of short stories. The stories are fictitious, but we hope the situations we describe and the questions we raise will help you consider different points of view on the ethical issues associated with genetic testing. The questions aren't necessarily intended to lead you to a set of answers. The purpose is to encourage you to think about the issues from a variety of perspectives.

These Discussion Scenarios may not address all the ethical issues or concerns related to genetic testing. We also recognize that we may not have asked all the 'appropriate' questions to help bring the issues to light or that are of importance to you, and realize that no choice of questions can be truly 'ethically neutral.'

This is why the questions are intended as a starting point for a broader look at the issues associated with genetic testing. We'll be revising the questions over time, so we encourage you to get back to us with new issues that you consider important.

Elsewhere in this web site, in the section called Whose Values? Who Decides?, we talk about the difference between individual and societal ethics. There are many situations where what we want as individuals may not be the same as what we expect our government to do. As you read the Discussion Scenarios, think about which questions in the stories should be left to the individuals or companies to decide, and which ones should be answered by society as a whole. We also look at two different philosophical viewpoints that underlie ethical decisions. In one of these traditions, decisions are evaluated based on their consequences. In the other, choices are based on a set of principles , regardless of the consequences. As you read each story, think about how these philosophical approaches and other kinds of information can help you reach your own conclusions on the ethics of genetic testing.

Visit geogene.com for additional information as well as information on DNA Genealogy, Genetic Engineering, Testing, Biology Basics and more.

Scenario A : Having Children; Exploring the Options

 

Faye and Michael want to start a family. But they know that both of their families have a history of Tay-Sachs Disease, an incurable condition that leads to deterioration in a person's brain. Children born with Tay-Sachs usually lose their eyesight after about a year, and rarely live beyond the age of five. 

Knowing that a person can carry Tay-Sachs without getting it, Michael and Faye asked their doctor for genetic testing first to determine if they are carriers and second to find out whether their future children might be at risk. Based on blood sampling, they found out that they were both carriers, meaning that a child they conceived naturally would have a one in four chance of being born with the disease.

Faye and Michael must now decide whether to conceive a child naturally, adopt a child, not have children at all or request pre-implantation genetic diagnosis (PGD). PGD is a relatively new technology where a number of Faye's eggs are fertilized by Michael's sperm in a laboratory.

Genetic testing identifies the embryos that are most likely to be Tay-Sachs carriers, or to acquire the disease, and those embryos are not reimplanted in Faye's womb.

Discussion Questions

1. If Faye and Michael decide to have a child, they want to do everything they can to make sure the child is not born with Tay-Sachs, since they believe this would be a very painful experience for the child, and for themselves. Is this a reasonable decision to make? Why or why not?

   Here are some of the alternatives available to Faye and Michael if they decide they want a child:

• They could conceive the child naturally, but terminate the pregnancy if a prenatal genetic test shows that the fetus has Tay-Sachs. The couple would have a choice of two tests chorionic villus sampling, which takes place after 10 to 12 weeks of development, or amniocentesis, which is carried out after 16 weeks of development. Both tests carry a risk of miscarriage, in the range of 1 in 500. The risk may be slightly higher for chorionic villus sampling.
• Another option is to use the relatively new technology of pre-implantation genetic diagnosis (PGD), where a number of Faye's eggs are fertilized by Michael's sperm in a laboratory. Genetic testing identifies the embryos that are most likely to be Tay-Sachs carriers, or to acquire the disease, and those embryos are not reimplanted in Faye's womb.

  This type of genetic testing takes place at a much earlier stage, and avoids the risk of miscarriage or harm to the fetus that can occur with amniocentesis or chorionic villus sampling. But the in vitro fertilization technique that accompanies the test has other drawbacks. Only one in four implanted embryos results in a pregnancy, and some women experience side-effects from the fertility drugs they have to take duringin vitro fertilization. The process is very expensive, is usually paid for by the couple, and is not currently available in all Canadian cities.

• The couple could adopt, knowing that their child will not likely have Tay-Sachs. However this may not be a realistic option if Faye and Michael are determined to raise a child "of their own flesh and blood."
• Can you think of any other alternatives available to Faye and Michael?

  Of the options we've listed, is one more or less acceptable than the others? To what extent is Faye and Michael's decision theirs alone? Are there social norms or values that would make any of the options more or less acceptable?

2. Should the public health care system ensure that genetic testing is available to any Canadian who wants it? Should the health system cover the cost? Should the system cover some tests, but not others? If some tests are not covered, to what extent should they be available to people who are willing to pay for them? Who should make these decisions, and on what basis?

Scenario B. Prenatal Genetic Testing

 

Adapted from a Scenario Composed by Ted Schrecker

 

Instead of dealing with a specific condition, this scenario refers to Condition X, to highlight the element of the genetic testing debate that has to do with the nature of the conditions to be detected.

Susan and her husband Jean-Claude know that there is a history of Condition X in both of their families. When Susan finds out she is pregnant, she asks her doctor whether there is a test that can determine whether the fetus:

• will be affected by the disorder; or
• will be a carrier of the disorder who can pass it on to future generations.

The test is available, so Susan and Jean-Claude decide to have it performed as early as possible in the pregnancy. Prior to having the test performed, Susan and Jean-Claude hear a radio interview with a medical geneticist, who says it would be truly unfortunate for a child to be born with Condition X when genetic testing can diagnose the disorder prenatally.

Discussion Questions -- Prenatal Genetic Testing

 

1. Let's say Condition X is Huntington's disease, and tests show that the fetus will develop the disease. Huntington's symptoms do not appear until a person reaches middle age, so that he or she could make constructive, informed life decisions with the information available through genetic testing. On the other hand, advance knowledge of what the future holds could be devastating for the person and his or her family, even before the disorder develops. Should Susan terminate the pregnancy, or carry it to term?
2. What if Condition X is familial hypercholesterolemia, a condition that increases the likelihood of dying of heart disease by middle age, but can be treated through diet and other choices?
3. What if Condition X is WAGR syndrome, a rare hereditary disorder that can involve mental retardation, several kinds of cancer, and genito-urinary abnormalities?
4. What if people with Condition X could live almost as long as anyone else, but only if they had access to full-time care, either at home or in an institution? If Susan and Jean-Claude continue the pregnancy, who should pay for that care?
5. Susan and Jean-Claude did not plan their pregnancy and therefore did not seek counselling to discuss their options before Susan became pregnant? What form of counselling would be appropriate now? Who should provide the counselling? How can individual choices be respected?
6. Are there genetic tests that should or should not be funded by the public health care system? Who should decide which tests are funded? What criteria should be used to determine which tests are funded? If some tests are not covered, should they be available to people who are willing to pay for them, and to what extent?
7. Do you agree with the view expressed in the radio interview with the medical geneticist? Does your answer depend on what Condition X is? How could the geneticist's point of view affect people who are already living with Condition X, and their families? How could our answers affect social attitudes, and even legal attitudes, toward people with genetic disorders?
8. Many genetic tests are now being developed and marketed by private companies. What should these companies, and industry as a whole, be doing to inform consumers and health professionals about the possibilities and limitations of genetic testing?

Scenario C. Selecting for Genetic Traits 

(Adapted from GenEthics Consortium Case Literature NHGRI at NIH)

 

Harry and Martha are worried about having a second child with Severe Combined Immune Deficiency (SCID). Children born with SCID have seriously impaired immune systems, as a result patients may succumb to any number of infections. As recently as 20 years ago, children with SCID died early in life, but the use of bone marrow transplants has greatly extended survival and, in some cases, led to better quality of life. In general, results are best when a transplant is done early, and when the marrow donor and recipient have similar genes that code for Human Leukocyte Antigens (HLAs). HLAs are a family of cell surface proteins that are critical for the activation of immune responses. The HLA genes are the most variable set of human genes knownand a close match is most likely if the donor is a brother or sister.

Harry and Martha have signed up with a new private clinic that offers pre-implantation genetic diagnosis (PGD). With this technique, a number of the woman's eggs are fertilized by her partner's sperm in a laboratory, and each of the embryos is tested before being reimplanted in her womb. This makes it possible to select embryos that are free of genetic disease.

Harry and Martha tell the medical geneticist they want to undergo PGD so they can begin their pregnancy knowing that the baby won't have the disorder. A few weeks later, they give a second reason: Their six-year-old daughter with SCID is getting sicker with the disease, and they hope to use bone marrow from a second child to save their daughter. Is it possible, they ask, to test the healthy embryos for HLA genetic compatibility and transfer only those that most closely match their daughter's type?

The geneticist knows that the technology can be used in this way, but wonders whether agreeing to the couple's request would be ethical.

 

Discussion Questions

 

Genetic Traits vs. Genetic Disorders

 

1. PGD can be used to identify embryos that are less likely to develop specific disorders, like muscular dystrophy or Down Syndrome. Harry and Martha asked the geneticist to select embryos that were free of the SCID mutation and had genes that were compatible with their daughter's. But a person's HLA status is not a disorder it's a genetic trait, just like his or her gender, or the colour of his or her eyes or hair.
   
   
   1. Is it ever appropriate to select an embryo based on genetic traits, rather than disorders?
   2. Should the decision be up to the individuals involved?
   3. Are there social norms or values that make it acceptable or unacceptable to select embryos for their genetic traits in certain situations?

Fate of the Unselected Embryos

2. The PGD procedure involves fertilizing a number of eggs in a laboratory (in vitro fertilization). In Harry and Martha's case, if the geneticist agreed to their request, only those embryos that were free of the SCID mutation and compatible with their daughter's HLA genes would be implanted.
1. What should be done with the embryos that have been screened out?
2. Should the couple donate them for medical research?.. store them for later use?... donate them to other couples for in vitro fertilization?...or have them destroyed?
3. Is the couple's decision completely up to them, or are there social norms or values that would argue for or against any of these options?