Genetic Testing and Family Planning
Published November 2019
The Health You Pass On
“Genetic testing gives people the information they need to plan their families,” says Northwestern Medicine Reproductive Geneticist Andrew F. Wagner, MD.
Thanks to advancements in genetic testing that have made it more accessible than ever, parents are better able to prepare to care for their children after they’re born.
“It used to be that only certain people were tested for certain gene mutations based on risk and ethnicity,” says Dr. Wagner. “Now we can do elective carrier screening for everyone, covering a panel of roughly 176 genetic conditions.”
What is carrier screening?
Your genes determine your traits. Sometimes, they can become altered. This is called a genetic mutation. Environmental factors, like ultraviolet radiation from the sun, can mutate your genes, or you can inherit mutated genes from your parents.
Carrier screening involves a blood test to identify genetic mutations you have the potential to pass down to your children. Most genetic mutations don’t affect health or give you a genetic disorder, but knowing about those that do can help inform your family planning decisions. If you and your partner both carry the same genetic mutation, your child has a one-in-four chance of inheriting it.
Is genetic testing right for me?
Genetic carrier testing is recommended for everyone. Traditionally, this is because of links between specific medical conditions and ethnicity:
- African American people are at higher risk of sickle cell disease.
- Eastern Europeans of Jewish descent and French Canadians are at higher risk of Tay-Sachs disease.
- Caucasians are at higher risk of cystic fibrosis.
- People of Mediterranean, African and South Asian descent are at higher risk of thalassemia, a blood disorder.
“Since we are a part of a multiethnic society and many of us may not know our exact ethnicity, I typically recommend carrier screening with a universal approach, where we screen for a number of conditions regardless of ethnicity,” says Dr. Wagner.
Your physician may suggest further screening for other concerns as well, such as unexplained infertility, miscarriages, unexplained seizures or malformations.
“Though additional genetic testing for certain groups has been common practice in obstetrics and gynecology, I advocate for everyone who is in the family planning or preconception phase to have carrier screening performed,” says Dr. Wagner. “It’s very possible that you may not know your full family history or exact ethnic background, which is why it’s important to gather as much information about your health — and your future child’s health — as possible.”
Here are some of the more common conditions that have a genetic link:
- Cleft palate
- Club foot
- Congenital heart disease
- Cystic fibrosis
- Gaucher's disease
- Huntington's chorea
- Fragile X syndrome, different forms of Down syndrome
- Muscular dystrophy
- Sickle cell disease
- Tay-Sachs disease
When should you do carrier screening?
“The optimal time to do carrier screening is in the preconception period, or pregnancy planning phase,” says Dr. Wagner. “You are able to do it at any time during pregnancy as well.”
What if you test positive for a genetic mutation?
If you’re not pregnant and test positive for a genetic mutation that you have the potential to pass down to your children, you can work with a reproductive genetic counselor to determine your options. An appropriate next step would be to have your partner tested for the same condition. For example, you could work with a reproductive specialist who can test sperm and/or eggs and select for fertilization and implantation those that do not carry the genetic mutation, in a process called preimplantation genetic testing.
If you are pregnant and test positive for a genetic mutation that you have the potential to pass down to your child, further screening or testing during your pregnancy may help determine if your child inherited this mutation — and help you and your physician formulate a care plan for the child’s arrival.
Carrier Screening for Peace of Mind
Whether you know of a genetic condition that runs in the family, or want to fill in the gaps in your family history while planning for a future family, carrier screening helps ensure that you’re as prepared as possible for the arrival of a child.
“Most of the time we’re sharing reassuring information,” concludes Dr. Wagner. “The three words that come up the most during my patient visits are ‘peace of mind.’ All of the screens and tests that we discuss in our genetic counseling visits are there to help out with planning, reassurance and decision making.”