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If you have an inherited retinal degenerative condition such as retinitis pigmentosa, Usher syndrome or Stargardt disease, should you get genetically tested? Is there a benefit in trying to determine the genetic variation that is causing your condition?
There are no quick and easy answers to these questions, but a genetic counselor can help you make an informed decision and help guide you through the process.
Kari Branham, a genetic counselor at the Foundation-funded University of Michigan Kellogg Eye Center, says that many people choose to get genetically tested, because “it helps them get a grasp of their disease; it helps them feel more in control.”
She adds that knowing the genetic cause can help the patient understand the disease, its inheritance pattern, and if their children or other family members are at risk. Identification of the genetic variation can also help predict the possible course of the disease — the timing and magnitude of vision loss. With more information about the possible visual outcome, people can make better decisions about careers and other lifestyle choices.
In addition, a genetic diagnosis enables people to determine their eligibility for human clinical trials of emerging treatments. Many of these clinical trials can only enroll persons with a specific genetic variation for the treatment under investigation.
Branham notes that the test may not be able to identify the genetic cause of their disease. “That can be frustrating for patients who are looking for an answer,” says Branham. “There are still a lot of genes we don’t know about.”
For example, finding the gene in recessive retinitis pigmentosa (RP) can be challenging. Stephen Rose, Ph.D., chief research officer, Foundation Fighting Blindness says, “Only about 50 percent of the genes responsible for autosomal recessive RP have been identified so people do not always get an answer. It can be particularly difficult to find the genetic cause of a disease when there is little or no other family history of the condition. However, FFB supported genetic testing labs keep testing stored samples as new genes are found, so with time, most people will learn what gene has caused their inherited retinal disease.”
The issues and circumstances associated with the testing of a child for a disease they may develop later in life can also be difficult. A genetic counselor can be particularly helpful in discussing whether genetic testing is appropriate for a child.
Costs of a genetic test can range from as low as $100 to more than $1,000 depending on the disease and potential genes under investigation. Some insurance companies will cover the cost.
Branham says that if you are considering being tested, contact a counselor before trying to navigate the process. A genetic counselor will help you determine if testing is an appropriate course of action, and if so, refer you to the most appropriate testing center. You may be referred to a clinician for additional exams and testing. A genetic counselor may also give you an estimate of how much time it will take to get a result, and the likelihood that the disease causing gene will be found. To find a genetic counselor in your area, visit the Web site of the National Society of Genetic Counselors, www.nsgc.org, or call (312) 321- 6834. Search on your zip code. (Note: Most genetic counselors listed on the NSGC Web site are qualifi ed to counsel people with an inherited retinal degenerative disease, even if they don’t list retinal conditions as a specialty.)
The Foundation Fighting Blindness has helpful information about genetics and genetic testing, which can be downloaded from www.FightBlindness.org. (Click on “Resources” in the menu below the home page banner to access genetic testing materials.)
DISCLAIMER: Physicians differ in their approach to incorporating research results into their clinical practice. You should always consult with and be guided by your Physician’s advice when considering treatment based on research results. |
