DNA banking an option for some families
We all have genetic susceptibilities toward different conditions because of the different alterations we carry. Although we all could potentially benefit from banking DNA, people with cancer or other genetic diseases can help their family by storing DNA for possible future testing. "For example, if testing is not feasible for the family or testing is not currently available, banking DNA can preserve a sample for future testing," said Christina Seubert, M.S., one of three genetic counselors in the Medical Genetics department. "The person who stores the DNA designates a person who can use it later, which is usually a child or grandchild. That way, if the person banking their DNA dies, his or her genetic information is still available to those designated family members."
People who know there is a family history of a certain disease, such as cancer, and want to know if they carry the alteration that contributes to the disease, can benefit from genetic counseling and testing. These people seek information before they have any symptoms of the illness, said David Schowalter, M.D., Ph.D., director of the Department of Clinical Genetics. In cases where cancer runs in a family, it's important to test a person who has been affected by the disease first, so researchers know where to find the genetic alteration that contributes to cancer. "If you test somebody directly, before they have symptoms, and you haven't tested a family member first, you can't give a positive answer," he said. "The concept is that you do this testing so you can tell someone definitely whether they're at increased risk."
Because more than one genetic alteration can increase risk, knowing where the alteration fits in the family gives geneticists a clearer picture of the test results. "For the positive result, you can be fairly clear," he said. "Either you have the alteration or you don't, and we're able to find it. For the negative result, which is what you want the patient to have, it's less clear."
"Even in the case of diseases for which a genetic connection has not yet been found, DNA banking can help," said Sajid Merchant, M.S., another genetic counselor. Over time, things change and new genetic testing may become available. "Therefore, we could offer testing on the banked sample, which might not have been possible earlier."
It can be helpful to have DNA banked on both affected and unaffected family members. This is the case with a specific form of family studies known as linkage testing, which requires DNA samples from multiple members within a single family.
DNA banking is currently offered at Marshfield Clinic. The banked DNA is not available to anyone for research testing, but rather only available for testing requested by the patient or his/her designee.
If you are interested in pursuing DNA banking or wish to learn more about it, please call 1-877-216-8535, or ext. 9-5999.
