Genetic Testing

Bryan W. Roberts
Philosophy, Logic and Scientific Method
Ph227 - Lecture 4

Background Reading:
Pence, Predictive Testing
Bayertz and Schmidt, Testing Genes and Constructing Humans - Ethics and Genetics

Overview of Genetic Testing

Many conditions can now be genetically tested for. However, there is a great deal of difficulty in deciding when we should test, as well as what the rules for use and treatment are on the basis of genetic information information.

A basic paradox to struggle with is the following. With a genetic test, a person learns something not only about themselves, but about their family as well. So, by not taking a genetic test, a person deprives their family of certain important information that might help their quality of life. But by taking a genetic test, on the assumption that your family will learn about any conditions you may have, you take away some of their autonomy in the sense that you deprive them of a right "not to know."

Case Study 1: Diabetes

2.9 million people in the UK live with diabetes. Another million are thought to have the disease without knowing it. And there is a sense in which genetic testing can clearly help.

The two main types of diabetes are Type 1 and Type 2; they are associated with both physical differences as well as different causes. But if gone untested and untreated, both can lead to significant physical problems such as kidney failure, blindness, and heart attack.

The propensity for both kinds of diabetes can be identified using genetic testing.

In addition, in the case of Type 2 diabetes, a significant amount of research suggests that high-risk adults can prevent or delay the onset of diabetes by improving their diet and the amount of regular exercise that they get.

This suggests that our quality of life can improved significantly by asking people to do a genetic test to determine there propensity for diabetes.

It has also led to a tendency to blame Type 2 diabetes patients, since their condition is often associated with lifestyle. However, there is a significant genetic component to their condition as well. So, it is not so easy to determine how many resources should be allocated to such patients.

Case Study 2: Nancy Wexler and Huntington's

Nancy Wexler is one of the most important researchers to have studied the neurodegenerative disease called Huntington's, and for which there is still no cure. Listen to her story.

The extreme deterioration of people with Huntington's leads about 1 out of every 10 Huntington's patients to commit suicide. 8 out of 10 Huntington's patients contemplate suicide.

Thus, there is a compelling argument that says that nobody should be tested for Huntington's. The risk of suicide is too great a harm to impart on a person who would otherwise live their life normally.

On the other hand, you must learn whether or not you have it so that you can make appropriate life decisions. For example, it may influence whether or not you want to have kids. If you have a partner, it may influence whether or not they want to have kids that share your risk to develop Huntington's.

Prevention versus Enhancement

In the case of Huntington's, nothing can currently be done to prevent the onset of the disease once it is identified. However, with tests for diabetes and many other diseases suggest preventative care.

As many as one person in every family is born with a condition that can be identified genetically. Many of these genetic markers can be identified and either aborted, or perhaps someday simply removed at the zygote stage, leading people to only bring to life children that do not have these genetic mutations.

There is a sense in which this just prevention, like getting an immunization to avoid infection. But in another sense this might be considered genetic enhancement.

People who are not able to avoid genetic deficiencies in this way are at a clear disadvantage and would almost certainly need some protection under the law to avoid unfair treatment.

For example, someone may be treated differently by insurance companies or state medical systems, or even have their treatment halted, on the basis of genetic information that suggests adverse effects. What makes such cases unfortunate is that a person may otherwise live a happy and healthy life in the absence of this information.

This is really the question to struggle with when it comes to genetic testing: to know, or not to know? And under what circumstances?

What you should know