Written by: Shannon McGrath, MSN, WHNP-C -AND- Elizabeth Platt, Genetic Counselor (Counsyl)
As a Nurse Practitioner, I do my best to help families achieve their dreams of adding to their families. One reason our pregnancy success rates at Red Rock Fertility are so high is because we include Pre-implantation Genetic Screening (PGS) in all of our IVF packages. It ensures we select the healthiest embryo possible for transfer. However, so many of my patients ask, what is genetic testing? So I enlisted the expertise of a genetic counselor at Counsyl. They are the wonderful company that handles our genetic screening and the experts that assist us in giving you the family you have been longing for.
My name is Elizabeth Platt, as a genetic counselor, I’ve worked with women and men in various stages of family planning. I review family histories, discuss genetic testing options, and guide people through family-planning decisions that work best for them. When couples are pursuing fertility treatments, they may worry about the risk of age-related chromosome abnormalities, like Down syndrome. In fact, there are other genetic diseases that have nothing to do with age and can be tested before a pregnancy is even achieved. Here, I review the top 5 questions to consider as you think about your family’s future.
1. “I just heard/read about genetic testing, what should I know? What should I think about? What should I be asking myself?”
A good place to begin is to consider a few of these questions below. The answers to each of these questions may be very personal, but can help you gain a sense of what information you’d like to obtain from genetic testing:
· What would I do with this information?
· What is important for me to know about?
· Does the test I am considering cover what I think it does?
· What would negative results mean for me?
· What would positive results mean for me?
· Who should I discuss these results with?
2. “What kinds of genetic tests are available to me at Red Rock Fertility?”
The physicians at RRF offer a variety of testing options specially chosen for their accuracy and scope. It is important to understand the differences between these types of tests, to help decide which is right for you.
Carrier Screening:
Carrier screening is a testing option that examines your DNA to determine if you carry any recessive single gene disorders. Recessive conditions are those which parents typically do not show symptoms of, but can pass on to their children.
You may remember from biology that genes are inherited in pairs, one from each parent. A carrier is a healthy person with one normal copy A and one abnormal copy a of a gene within a pair. For most of the diseases included in carrier screening tests such as the Counsyl Test, as long as you have one normal copy of the gene, you’re okay. You’re just a carrier; nothing more, nothing less.
Testing for chromosome abnormalities:
Chromosomes are the structures that contain all the genetic information that is necessary to ensure we grow and develop as we should. A chromosome can be thought of like a cookbook, and our bodies require a complete set of cookbooks (23 pairs of them, in fact) to be completely healthy. Each cookbook is filled with “recipes” similar to our genes, in that they provide the specific instructions our bodies require for health.
Chromosome disorders are most often the result of an error that occurs in the process of cell division. Sometimes an entire cookbook gets lost or added in the process, along with all of its crucial recipes. Some of these errors result in miscarriage, and others can cause disorders like Down syndrome. Because these disorders occur at the time of conception, they cannot usually be tested for prior to pregnancy.
PGS (Pre-implantation Genetic Screening) and PGD (Pre-implantation Genetic Diagnosis) are available as part of the process of in vitro fertilization (IVF). When the sperm and egg are united for fertilization, they form microscopic embryos. These embryos can be analyzed for chromosome content to determine if the correct number of chromosomes is present. Through PGD, embryos can be further tested for specific genetic diseases, like the ones included in the Counsyl carrier screen.
3. “How does carrier screening work? What doesit cover?”
Historically, carrier testing has been offered to people based upon their ancestry, as some of these conditions are more common among people of particular ethnicities. However, recent changes in technology have made it possible to test for more conditions at a lower price. This is particularly important today as our society has become such a melting pot of ethnicities; and truthfully, few of us really know about our ancestry beyond one or two generations. Studies have shown that relying on self-reported ethnicity can sometimes lead to missed carrier states.
Expanded Carrier Screening and the Counsyl test were designed to address this issue. By screening everyone for the same conditions, your doctor can provide you with valuable information as you embark on your fertility plans. At Red Rock Fertility, the Universal Panel includes 103 diseases including some you may be familiar with, like cystic fibrosis, Tay Sachs disease, and sickle cell anemia. While no genetic test has a 100% detection rate, current technology allows us to cover the most common gene changes for each of the diseases tested. As many women and men have relayed, this testing provides peace of mind and the opportunity to prepare in an otherwise uncertain phase of life.
4. “I don’t have a family history of any significant diseases. Is genetic testing and carrier screening important for me?”
Since carriers of recessive diseases do not typically display symptoms of the disease, most are unaware of their potential risks. However, studies show that most of us are carriers of some recessive genetic disease— even if we are young, healthy and do not have a family history. What you really want to know is whether you and your partner are carriers of the same genetic disease.
The vast majority of couples that give birth to a child with a recessive disease have no family history of that disease. In fact, 80% of children with cystic fibrosis are born to parents with no known family history of cystic fibrosis. These types of conditions can be present in a family for many generations, but they do not appear unless someone who is a carrier has a child with another carrier. In addition, chromosome disorders such as Down syndrome, Turner syndrome, and trisomy 16 do not usually appear in the family history. Bottom line: family history matters, but it is not the only tool to rely on when trying to figure out what tests you want to pursue.
5. “Where can I go to find out more information about genetic testing?”
Obviously, you can speak with the physicians and nurses at Red Rock Fertility regarding any testing you may be considering. However, there are a number of online and written resources that may be helpful, too, as you weigh the options. Many of my previous clients have found these websites to be quite helpful in this regard; I hope that you will, too.
- Red Rock Fertility /in-vitro-fertilization-ivf/
- Counsyl www.counsyl.com
- American Pregnancy Association http://americanpregnancy.org
- Genetics Home Reference http://ghr.nlm.nih.gov
- March of Dimes http://www.marchofdimes.com/index.aspx
- American College of Obstetricians and Gynecologists FAQs http://www.acog.org/~/media/For%20Patients/faq179.pdf
