Navigating Family History: Understanding Cystic Fibrosis Carrier Screening
Family history plays a significant role in shaping our understanding of potential health concerns. If you have a family history of cystic fibrosis (CF), a genetic condition that most often affects the lungs and digestive system, you might be wondering about your chance of being a carrier. Carrier screening is an option that can provide valuable insights into your genetic makeup and help you make informed decisions about family planning. In this blog post, we'll explore carrier screening in the context of a family history of cystic fibrosis; however, these concepts can be applied to family histories of other conditions as well.
Understanding Cystic Fibrosis
Cystic fibrosis (CF) is a genetic condition caused by changes in both copies of the CFTR genes which makes them not to work in the way they are expected. This gene is responsible for producing a protein that regulates the flow of salt and fluids in and out of cells. In individuals with CF, this protein is either absent or not working, leading to thick and sticky mucus buildup in the lungs and other organs. This can result in breathing difficulties, lung infections, digestive problems, and other complications. There are treatments available and many individuals living with CF. The Cystic Fibrosis Foundation has great content to learn more about the condition.
Family History and Carrier Status
If you have a family history of cystic fibrosis, it means you may have a higher chance to be a carrier than someone who does not have a family history of cystic fibrosis. The reason for this is because the parents of the person with cystic fibrosis are likely carriers. A carrier is someone who has one copy of their CFTR gene with a change in it, but they have another copy of the gene that works fine. Their other copy of the gene can be enough to ensure the person does not have symptoms of cystic fibrosis. Because a carrier usually has no symptoms of the condition, it is not known who is a carrier until there is carrier screening performed or a child diagnosed with the condition. The CFTR gene with the change in it can be passed on from generation to generation without anyone knowing.
Carrier Screening
Carrier screening is a genetic test that can provide information about your genetic makeup and your chance of passing on genetic conditions like cystic fibrosis to your children.
How Carrier Screening Generally Works
Carrier screening typically involves a blood test or a saliva sample. The test looks for specific genetic changes associated with cystic fibrosis and other conditions, if you choose. Sometimes one person of a reproductive pair proceeds with carrier screening and depending on their results, their partner or donor may choose to undergo carrier screening. Other times, both members of a reproductive pair have simultaneous carrier screening, so they receive their results at the same time.
If you and your partner/donor are both carriers, then there is a 25% chance your pregnancy could inherit both copies of the gene that have the change. If only one of you is a carrier, then there's a low risk of your child having CF, but there's a 50% chance they could be a carrier. If neither of you are carriers, then the chance for your child to be a carrier or have cystic fibrosis is very low.
Important Consideration for Family History of CF
For families where one member has CF, it is important to know what specific gene changes that relative has to ensure the carrier screening looks for those changes. Carrier screening broadly looks at changes that can cause the CFTR gene not to work as it is supposed to. However, there are thousands of changes, so it is important to take the time and confirm the carrier screening lab looked at the changes in the family. Otherwise, it is possible that you receive negative carrier screening results but could still be a carrier of the specific change in the family.
To ensure the carrier screening lab evaluated your CFTR thoroughly, obtain a copy of your family member’s genetic report and share it with the carrier screening lab. On your relative’s genetic test report, it will state what genetic changes they have and the lab can compare your results to theirs.
Empowering Informed Choices
The information gained from carrier screening can be used to make informed decisions about family planning. If both members of a reproductive pair are carriers, then options like in vitro fertilization (IVF) with preimplantation genetic testing (PGT) to select embryos without the CF mutation before they are implanted can be considered. Donor egg, sperm, or embryos can be considered as well. Or, if IVF is not an option, then testing a pregnancy through CVS or amniocentesis may be a possibility. Testing a baby after birth is also an option. Sometimes, carrier screening is not desired and the pediatrician is instead informed of the family history to ensure proper screening of the baby after birth is done.
What about Newborn Screening?
Newborn screening is performed on all babies right after birth for select conditions, including cystic fibrosis. However, newborn screening is not perfect, so it may still be important to do additional testing after a baby is born to assess their chance of having cystic fibrosis. Informing the pediatrician and all other providers is important, so they can ensure the appropriate testing can occurred. Early identification may be helpful for treatment options and overall planning.
Carrier screening offers insights that empower you to make informed decisions about family planning, ensuring the best possible outcomes for your future family. By understanding your genetic makeup and the options available to you, you can make choices that align with your values, set expectations, and understand treatment and care. If you have concerns about your family history of cystic fibrosis, reach out to a genetic counselor or healthcare provider to discuss carrier screening’s benefits and limitations.
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* This blog constitutes general information about genetic testing and medical screening. This blog does not offer or provide medical advice or diagnosis, and nothing in this blog should be construed as medical advice or diagnosis. Do not rely on the information in this blog/article to make medical management decisions. Please consult with a medical professional before making those decisions. Do not delay in seeking professional medical advice if you think you have a medical concern. Do not disregard professional medical advice based on any information received in this blog.
