Genetic testing can be divided into two basic types: diagnostic and predictive. Diagnostic tests involve determining the cause of a disease in a patient with symptoms, much the same as standard blood tests or x-rays would be used. Predictive tests are those in which a person is found to be at increased risk for a disorder, but no symptoms of the disorder are present. There are fundamental differences in the ethical and procedural issues involved in using these different forms of testing.
Ethics of Genetic Testing
Diagnostic genetic testing for heritable disorders has been in common medical practice for more than thirty years, well before the advent of DNA technology. In fact, some tests still rely on non-DNA methodologies. The most well known example is the study of hemoglobin to diagnose hereditary blood disorders, such as sickle cell disease and thallasemias. Even though DNA testing is available for these diseases, electrophoretic analysis of hemoglobin is still the method of choice in most situations.
Generally, patient consent specifically for genetically based diagnostic tests are not required. It is fundamental to management of a patient for the physician to know the nature of the disease in question. Predictive testing is a much more complex matter. As the availability of predictive testing for various medical conditions continues to grow, the question as to whether these tests should be performed has stirred a great deal of debate. Among the myriad of questions, one is at the core: Is it better to know or not to know that you have the genetic makeup to develop a disease or condition?
On the affirmative side of the debate, genetic testing offers people an opportunity to take unprecedented proactive measures to safeguard their health and even prolong their lives. The Adult Onset Genetic Disease Program at University Hospital tests only for genetic conditions for which there is a treatment or treatments, and that is an important distinction to make. Testing without viable treatment options opens a Pandora’s box of problems, such as anxiety or depression.
If a genetic test is desired, it should be done with the assistance and support of certified genetic counselors. "Mail order” genetic testing services are available, but getting a generic results form is no match to having a trained genetics counselor discuss all aspects of testing and the results face to face. When the results are positive, a genetic counselor presents the options for treatment in an objective manner. Receiving tests results can be an emotional experience, even if the test shows someone is not predisposed to developing a condition. A genetic counselor can also help patients deal with the emotions or refer them to a mental health professional for additional support.
Privacy and discrimination issues are at the forefront of any discussion involving genetic testing. Many states, including New Jersey, have laws that protect the privacy of people who undergo genetic testing. The New Jersey Genetic Privacy Act states that test results cannot be released to anyone without specific, written consent from the patient and prohibits discrimination by insurance companies.
When it comes to testing children, it’s generally agreed that testing for late onset diseases should be deferred until they can make their own decisions. An exception is when the disease can present during childhood or adolescence, such as is the case with familial adenomatous polyposis, a type of heritable colon cancer.
Genetic testing can provide important information, but whether or not to be tested is a matter for an individual to decide after being fully informed about all of the implications: what a positive and a negative result actually means, and what the consequences of the test results have for family members who may or may not want to know.