Gene Testing: Helpful Knowledge or Harmful Information?
By Christina M.H. Powell
Pastors live and minister in exciting times. Medical and scientific advances, such as the completion of the Human Genome Project in 2003, bring promises of new knowledge for treatment of diseases. But they also bring new ethical questions on how this vast wealth of biological information should be used.
According to the Human Genome Program of the U.S. Department of Energy, more than 900 genetic tests are available. Pregnant women, newborns, adults with a family history of certain diseases, and adults with illnesses whose diagnosis can be confirmed by genetic means may undergo genetic testing. Many church members will encounter genetic testing at least once in their lives. As a result, ministers may be called on to provide a Christian perspective to church members seeking counsel when faced with the ethical issues surrounding these genetic tests.
What Is A Gene Test?
Genes come in pairs. One copy is inherited from one’s mother and one copy is inherited from one’s father. Genes make up the chemical blueprint that determines a person’s inherited potential and limitations. Some genes determine external traits, such as eye color, while other genes determine less obvious traits, such as a predisposition to diabetes, heart disease, or certain types of cancer. More than 4,000 diseases, such as cystic fibrosis, Tay-Sachs, and sickle cell anemia, are genetically inherited.
A gene test involves taking a small sample of blood, body fluids, or tissues to extract DNA from cells found in these samples. The DNA may show a change from normal cell’s DNA. This can be as subtle as a change in or the absence of one link in the DNA chain (a missing or mutated chemical base). Some changes are obvious enough to detect under a microscope — a missing or added piece of an entire chromosome or even an extra chromosome (such as in Down syndrome). A genetic test is a broader term that includes tests for the presence or absence of key proteins that result from altered genes.
The most common use of genetic testing is newborn screening for inborn errors of metabolism, such as phenylketonuria. Phenylketonuria is a genetic disorder caused by a lack of an enzyme necessary for metabolizing the essential amino acid, phenylalanine.
When Is A Gene Test Helpful?
Newborn screening for diseases such as phenylketonuria is beneficial. A gene test can alert doctors and parents to make timely dietary changes for a newborn to prevent mental retardation.
Gene tests can be beneficial for adults as well. For example, a gene test that determines whether an individual in an affected family has inherited a gene for adenomatous polyposis can lead to the timely removal of colon growths and save an individual’s life.
Whenever a gene test can be used to guide a physician to the appropriate treatment for patients, the test has the potential to dramatically improve lives. In this context, we can view gene testing as a blessing.
What Are The Limits Of Gene Tests?
As with all developing technologies, gene testing has its limits. For some adult-onset diseases such as Alzheimer’s disease and certain cancers, the interpretation of gene test results and the determination of appropriate treatment is complex.
Gene tests work well for people who have no symptoms of the disease but are considered high-risk because family members have the disease. But tests can only give a probability for developing the disorder. Some who carry a mutated gene associated with a disease may never develop the disease. The scientific term for the probability of getting the disease when mutation is present is gene penetrance. Incomplete penetrance is the scientific term used for an individual with a mutation who may never get the disease.
For genes that show incomplete penetrance, many factors may come into play that keep the diseased condition from taking place. Perhaps more than one mutated gene is needed to cause the illness or certain environmental factors must be present in addition to genetic mutation for the disease to manifest itself.
One such disease is a rare, inherited form of breast cancer for which predisposition tests have been available since 1996. Most breast cancer cases occur in women who have no family history of the disease. However, nearly 10 percent of breast cancer cases are inherited (familial). In these familial cancer cases, mutations in two genes called BRCA1 and BRCA2 (for BReast CAncer), are thought to be involved. More than 200 mutations have been found in the BRCA1 and BRCA2 genes, and each family typically carries its own characteristic mutation. While research suggests women who carry these mutations run an increased risk of developing breast cancer, some women who have the mutations never develop the disease.
Also, the presence of a mutated gene does not indicate the severity of a disease. For example, genetic testing may enable a pregnant woman to know her unborn child carries the gene for cystic fibrosis. The test, however, will not indicate if her child will only have a mild cough or will have severe lung problems leading to fatality before 30 years of age.
Different mutations of the same gene can lead to differing degrees of symptoms. More than 700 mutations exist in the gene responsible for cystic fibrosis. Not enough is known about which mutations lead to which set of symptoms. The scientific term for this issue is gene expressivity.
All medical tests, including gene tests, are subject to the possibility of laboratory errors — sample misidentification, or contamination of the chemicals used in processing samples. While such mistakes are rare, they remain a limitation of gene testing that must be considered.
When Could A Gene Test Be Harmful?
Occasionally the technology for testing for a given gene outpaces the technology for treating the condition that is discovered. In the example of inherited forms of breast cancer, while it is possible to screen for BRCA1 and BRCA2 mutations, there is no clear strategy for appropriate follow-up for those carrying one of these mutations. Two possibilities for treatment include increased surveillance, such as more frequent mammograms, or the removal of healthy breasts as a preventive measure. Surgery, however, carries its own risks, and there is no guarantee all tissue capable of becoming cancerous will be removed.
Gene testing carries potential psychological risks for those diagnosed with a mutant gene. These include increased anxiety and depression. The resulting depression can lead to an increased risk for suicide in some individuals.
Individuals who learn they did not inherit a harmful mutation while other family members did may experience survivor’s guilt. Tension may develop between family members when they receive test results. Psychological risks can extend to a patient’s children as well, since children are at risk for inheriting mutant genes from parents. A chaplain or pastor can provide a much-needed spiritual perspective in these situations, as well as promote harmonious family relationships in the wake of their receiving disturbing test results.
Another potential risk of genetic testing is discrimination in obtaining insurance and employment. The identification of a mutant gene might constitute a pre-existing condition that may be excluded from insurance coverage. If test results became part of one’s medical record, a future employer could access them and these results might influence a hiring decision. Yet, if people identified as high-risk withhold results from their insurance company, they may experience difficulty getting their insurance company to pay for frequent screenings or other preventative measures that are needed in light of their test results.
Prenatal genetic testing involves unique risks. While one potential use of prenatal gene testing is to prepare prospective parents for the birth of a potentially handicapped child, prenatal testing also can influence the choices made concerning the life or death of an unborn child. Identifying Down syndrome, cystic fibrosis, or other chromosomal disorders often results in the parents terminating the pregnancy.
Some prenatal tests, such as chorionic villus sampling (CVS) and amniocentesis, can cause a miscarriage. A 3 to 5 percent miscarriage rate is associated with CVS when performed between weeks 10 and 12 of a pregnancy. The risk of miscarriage following amniocentesis (performed at 15 to 18 weeks gestation) is between 1 in 400 to 1 in 200.
Many limitations to gene testing already discussed also apply to prenatal gene tests. However, when the decision arising from the test results is whether or not to terminate the pregnancy, a testing error may lead to the tragic loss of a developing life.
What Is The Biblical Perspective?
While gene testing cansave lives, improve health, and even aid realistic planning for future medical needs, ministers need to be aware of its limitations, its potential for harm in specific situations, and its spiritual implications. Gene testing at any age can lead to a fatalistic outlook on life that fails to consider the sovereignty of God. Christians believe God knows the number of their days (Job 14:5; Psalm 39:4) and that He is the Great Physician. In many cases where a gene test shows a genetic predisposition for a disease (incomplete penetrance), lifestyle and dietary changes may prevent disease symptoms from ever appearing. In these cases, patients are encouraged to apply godly wisdom to their diet, exercise, and lifestyle habits.
Prenatal gene testing raises ethical issues regarding the value of human life. What genetic handicap renders a life not worth living? What message do we send to disabled adults when doctors and parents decide to end the life of an unborn child who has the same handicap? Beyond the more obvious sanctity of human life issues, prenatal testing and the option of terminating a pregnancy reflect conditional parental love. Often a mother awaiting prenatal test results holds her pregnancy and developing child at an emotional distance until she can be sure the child is not handicapped and the pregnancy will continue.
Many times couples agree to routine prenatal tests and are suddenly forced to make hard decisions in a short period of time. It is important for prospective parents to clarify their values and fully understand the nature of any medical test before giving consent.
What General Principles Can Be Learned From Gene Testing?
Gene testing is a developing technology that can illustrate important principles about other medical technologies. Gene testing provides information. Information itself is morally neutral, but what people choose to do with information can have moral implications. Information can be used to save lives or as a rationalization for ending life. Information can bring hope and reassurance or increase one’s anxiety. Information can be used to help people or discriminate against people. Some information may overwhelm people. Treatment technologies often lag behind diagnostic technologies. Sometimes, perhaps, people are better off without information.
Ministers must realize discernment is necessary whenever people are faced with decisions regarding the use of new medical technologies. Pastors need to avoid extremes such as blanket condemnation of new scientific techniques as well as wholesale acceptance of the latest supposed medical advance. Rather, pastors need to encourage people faced with decisions regarding medical testing to ask their medical providers questions and make sure they understand the important issues involved before they consent to any test or procedure.
Finally, ministers need to be prepared to meet the spiritual and emotional needs of those receiving medical treatment for physical needs. Gene testing can bring powerful emotions to the surface because patients are faced with difficult issues such as family dynamics, attitudes toward disability, and one’s own vulnerability and mortality. Spiritual issues such as God’s sovereignty, the sanctity of human life, and one’s eternal destiny arise as a patient prepares to receive test results. My prayer is God will prepare each minister with the wisdom, discernment, and sensitivity to guide those under his care who encounter the complex issues related to genetic testing.