Planning for Pregnancy When You or Your Child has a Rare Genetic Disease
Photo by Guillaume de Germain on Unsplash
By Elizabeth Kearney, MS, CGC, MBA
Families affected by rare genetic disease may have questions about whether others in the family will develop the disease, particularly if they or their children are affected. Here is some advice from a genetic counselor.
I have a child with a rare genetic disease. What are the chances that my next child will have the disease?
In most cases, people who already have a child with a known genetic condition still have a very good chance to have another child without the same disease. However, their chance for a second child with the same condition may be higher than other people.
Genetic diseases have different inheritance patterns, or ways they are passed within a family. Some conditions are very unlikely to happen again, but others may pose a higher risk. Knowing the inheritance pattern for the particular disease allows a prediction of the chances the next child will have the condition.
I have a rare genetic disease. Will my child have a rare disease?
Just because someone has a genetic disease does not mean they will definitely have a child with the same condition. People with rare genetic diseases may have a very good chance to have a child without the condition, but they may have a higher chance. As stated above, it depends on the genetic condition and the type of inheritance pattern.
Should people with a family member affected by a rare genetic disease have genetic testing?
Genetic testing can be a valuable tool for parents-to-be. There isn’t one single genetic test that can give all the information about a future baby’s health. Therefore, it’s important to talk with someone who is knowledgeable about genetic testing, like a genetic counselor, about what type of genetic testing is appropriate.
What are my options if I am planning to have a child in the near future and have a higher chance for a rare genetic condition?
If people planning to have a child know they have a higher chance for an inherited condition in that child, there may be several options available, depending on the particular condition.
Testing embryos: In vitro fertilization or IVF can be used to allow special genetic testing, called preimplantation genetic testing (PGT), even if a woman or couple has no fertility issues. PGT allows testing of embryos before they are transferred to a woman’s uterus during the IVF process. In PGT, the IVF center takes a small number of cells from the outer layer of an embryo at five days of development. A special genetic testing lab can perform genetic testing on this small number of cells from the embryos to look for the non-working gene or genes that cause disease. The IVF center will then transfer only the embryos without the disease into the woman’s uterus.
Although this additional genetic testing adds some costs, it may be preferable to testing a pregnancy. Testing a pregnancy can carry ethical dilemmas for the parents if a problem is found and they have to decide whether to continue the pregnancy. Many women and couples feel more comfortable testing an embryo and only transferring embryos that are not affected by the inherited condition. Although testing embryos during IVF is available to any couple, it might not be discussed with a woman if she doesn’t have genetic testing ahead of time to find out if she carries any genes for inherited disease.
Testing a pregnancy: Special medical procedures called chorionic villus sampling (CVS), done in the late first trimester, or amniocentesis, done in the second trimester, allow genetic testing to show whether a child has an inherited disorder that is known in the family. During CVS, a catheter is inserted through a woman’s cervix to obtain a small amount of tissue from the placenta. With amniocentesis, a thin needle is inserted through the mother’s abdominal wall and uterine wall to obtain a small amount of the fluid around the baby. (With CVS and amniocentesis, there is no need to touch the developing baby because the tissue or fluid contain cells, which have DNA.) A laboratory uses the tissue or fluid to look at the baby’s DNA. CVS and amniocentesis carry a small risk for pregnancy loss, so parents-to-be need to weigh the benefits against that risk.
If the results of genetic testing through CVS or amniocentesis show that the fetus has an inherited disorder, the parents will need to decide whether to continue the pregnancy. If they decide to continue, knowing in advance can help manage their pregnancy and delivery plans. For example, some inherited diseases require medical intervention right away at birth, so it can be smart to deliver at a special medical center. Knowing in advance that the child has an inherited disorder can improve treatment for that child and in some cases, even allow access to drug treatments or surgeries.
Although prenatal testing is available to all pregnant women, some prenatal care providers may not offer this option unless they know that women have an increased risk of a genetic disorder. Pregnancy is a sensitive time and it can be helpful to consider options in advance.
Using an egg donor: Some women and their partners who know they carry DNA findings responsible for serious inherited disorders do not want to pursue genetic testing on embryos or during pregnancy. They may still have options. Many IVF centers work with egg or sperm donor agencies and can help a woman and her partner find a suitable donor.
Adoption: Understandably, many people want to have another child that is genetically their own. But every person’s journey is unique, and some people change their minds about adoption. Perhaps they realize that the experience of parenthood, not a genetic relationship with a child, is what they seek.
Not having more children: Some people find other ways to direct their parenting instincts. Channeling energy into causes that support children or into other family members, like nieces and nephews, can be very satisfying.
Can my doctor help me with determining my chances for a healthy child?
Many people with a higher chance to have a child with a rare genetic disease may assume that their regular care provider, fertility clinic, or prenatal care provider can help them get started with genetic testing and exploring options. However, it can be hard for busy physicians or nurse practitioners to keep up with the advances in rare disease or genetic testing. Most will ask some basic family health questions and will offer some standard genetic testing. However, studies show that about 10% of couples have a genetic risk to their baby that routine prenatal care did not identify.1
Therefore, to get started, people with a known rare genetic disorder in the family may want to seek services from a genetic counselor. A genetic counselor is a healthcare professional who is an expert in genetics and can help families determine whether there is a higher chance for inherited disease in the family and what genetic testing and options are available to them.
How can I find a genetic counselor?
People can locate a genetic counselor by visiting the National Society of Genetic Counselors website, www.NSGC.org or consider a telehealth genetic counseling service.
The important thing is to start early and ask the right questions to be sure as many options as possible are available.
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Elizabeth Kearney, MS, CGC, MBA is a licensed genetic counselor and founder of Mainstream Genomics, LLC, which aims to help people who are pregnant or planning for pregnancy find the right genetic services for them. She is a past President of the National Society of Genetic Counselors and speakers nationally and regionally as a thought leader in genetic service delivery. Liz has a Master’s in Human Genetics From the University of Michigan and an MBA from Kellogg School of Management at Northwestern University.
Elizabeth Kearney, MS, CGC, MBA
Founder and Licensed Genetic Counselor
Mainstream Genomics, LLC
https://www.mainstreamgenomics.com
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Mainstream Genomics offers an online service designed to make it easier for people to learn their chances to have a healthy baby. The founder is a licensed genetic counselor who is a past President of the NSGC and has over 25 years of experience. People can complete an online, secure family health history form. A genetic counselor will review the information and create a personalized screening plan, as well as a report to give to a primary care , prenatal, or fertility doctor. A phone or video appointment with a licensed genetic counselor is also included with the service.
Meschede, SD and Horst, J. The practical importance of pedigree analysis in women considering invasive prenatal diagnosis for advanced maternal age or serum screening. Prenatal Diagnosis 2000.
