In the age of the Internet, where cybercondriacs are just a mouse click away from a diagnosis, do-it-yourself home genetics test may seem like the next logical step in managing health. But these tests, which are relatively new and available online, are often not comprehensive and may cause unnecessary stress, warns Suzanne Mahon, DNSc., a clinical professor of hematology and oncology at Saint Louis University.
According to Mahon, a recent undercover investigation by the Government Accountability Office, found that home genetic tests from the top four genetic test companies often provided incomplete, conflicting and misleading information to consumers.
"Sometimes a little bit of knowledge can be a dangerous thing. This is one of those cases," said Mahon, who provides genetic counseling at the Saint Louis University Cancer Center.
"When geneticists order testing, they have selected the appropriate test based on a family and personal history. He or she also can help you understand the results and decide what to do next."
Unlike home pregnancy tests which are fairly simple and test for the presence of a specific hormone, genetic tests are much more complicated. Typically, home genetic tests are not capable of providing complete DNA sequencing, which according to Mahon, is the best way to define hereditary risk. For example, home genetic tests do not test for all forms of hereditary breast cancer. Without comprehensive testing, Mahon says the results are not meaningful.
Mahon also worries that home genetic test users will not be prepared for the results or know what to do with the information.
Using Genetics to Assess Breast Cancer Risk
The discovery of the breast cancer genes BRCA1 and BRCA2 has made breast cancer one of the most commonly requested genetic tests for disease susceptibility. Women who are diagnosed with breast cancer before age 50, have bilateral cancer, have a family history of breast cancer should talk with their health care provider about genetic testing.
"Approximately 10 percent of the population has a hereditary risk for developing cancer especially cancers of the breast, colon, ovary, uterus, and malignant melanoma. If you think you may be at risk, you should talk with your health care provider about genetic testing. He or she might then refer you to a geneticist, who will conduct a risk assessment to see if genetic testing might be helpful," Mahon said.