Carrier screening is a test that can help determine if you are likely to have a child with genetic disorders. Carrier screening tests for certain variants of genes that may manifest as genetic conditions. Such testing provides vital genetic information that empowers couples with knowledge on how to proceed with starting their family.
What is Carrier Screening?
Every individual receives a set of genes from the father and one from the mother. Due to the complex mechanism of duplication of the DNA, there is a possibility of certain changes in the sequence of the DNA resulting in the formation of variants. Most variants are harmless and possibly do not manifest into a condition.
If a person has one variant and one normal gene, he/she is called a carrier. The carrier does not show any physical symptoms of the disease, since they have one normal copy of the gene. If such an individual were to birth a child with a partner who also carries a similar gene variant, there is a likelihood that the child may receive both variant genes leading to a genetic disorder.
In many cases, a variant may be passed on through generations and still not be detected.
Thus it is advisable to perform genetic carrier screening before attempting pregnancy, either naturally or through assisted reproductive technologies like IVF, IUI.
What are the Genetic Diseases for which Screening is Advisable?
Genetic screening is used to test for autosomal recessive and X-linked disorders. An autosomal recessive disorder is one where the individual inherits two mutated genes (or variants), one from each parent (who are carriers). Examples of autosomal recessive genetic disorders include cystic fibrosis, spinal muscular atrophy, sickle cell disease, or Tay-Sachs disease. X-linked disorders are caused due to mutations of genes on the X chromosome. Examples of X-linked disorders are Fragile X syndrome or Duchenne muscular dystrophy.
Since genetic carrier screening is not a mandatory aspect, there are many options for testing. There are, however, certain recommendations, that one should follow. For instance, the American College of Obstetricians and Gynecologists (ACOG) recommends that all individuals who intend to achieve pregnancy must be screened for spinal muscular atrophy and cystic fibrosis. ACOG also recommends screening for Fragile X syndrome in certain specific cases – cisgender females and transgender men with a family history of X-related disorders.
, There are some genetic disorders that show strong racial relationships with individuals of a particular ancestry or belonging to specific ethnic groups are more prone to certain genetic disorders than others. For example, individuals who have African, Mediterranean, Middle Eastern, Southeast Asian, or West Indian ancestry should be tested for blood-related genetic disorders like thalassemia and sickle cell anemia. Individuals having Ashkenazi Jewish ancestry are at an increased risk of genetic disorders like cystic fibrosis, Canavan disease, familial dysautonomia, and Tay-Sachs disease.
Apart from these recommended tests, some women may choose to get tested for a much broader range of genetic disorders, regardless of ethnicity. This is called expanded carrier screening and may include tests for 100 to over 500 genetic disorders.
As already mentioned, there are many options for testing and it is always advisable to talk to your physician and fertility expert before deciding on the best course of action.
Test Results and How to Make Sense of It
Typically, the most common method for carrier screening is to start with the woman who is providing the eggs. If she returns a positive result on any one (or more) of the genetic disorders tested, then the male partner should be tested to make sure he is not positive for the same genetic disorders. In case of a negative result, the male partner doesn’t necessarily need to be tested The exception here is the Fragile X syndrome, where only the mother has to be positive (carrier) for the test to put the pregnancy at risk. However, most fertility specialists test both the male and female partners at the same time so that any genetic issues in either person are detected. This also saves time if the patients need to have their fertility treatment done quickly for any reason.
For a child to inherit a genetic disorder, both parents must have a recessive variant (mutation) in the same gene. Even in this case, there is only a 1-in-4 (25%) chance that the child will inherit both mutated genes and be affected by the genetic disorder. There is a 50% chance that the child will inherit one working and one mutated gene, making him or her a carrier, just like the parents. There is also a 25% chance that the child receives both working genes from the parents and is neither a carrier nor affected by the genetic disorder. In the case of X-linked disorder, there is a 50% chance of the child inheriting the genetic disorder. If the child is a male, he will have XY chromosomes and will inherit the genetic condition. If the child is a female, she will have XX chromosomes, meaning one working and one mutated gene, in such cases, she may only be mildly symptomatic.
Regardless of the number of genetic disorders you test for, you simply cannot test for all genetic changes. So even if you test negative on all your carrier screening tests, there is still a slim possibility of some kind of disability in the child that is attributable to genetic mutations but cannot be detected through testing.
Preimplantation Genetic Testing and its Implications in Family Planning
Preimplantation genetic testing (PGT) is the genetic screening of embryos formed during in vitro fertilization (IVF) before they are implanted into the uterus of the woman. This procedure, while optional, is a powerful tool in the hands of clinicians and intended parents to choose only those embryos that do not show any genetic aberrations for implantation.
For couples trying to achieve pregnancy through assisted reproductive technologies like IVF, PGT helps choose the right embryo and the risk of the child being born with a genetic disorder is dramatically reduced, especially if both parents are carriers.
Genetic testing can also be performed during pregnancy (prenatal), either in the first trimester (by chorionic villus sampling) or in the third trimester (by amniocentesis). The information is very helpful in planning for a safe pregnancy as well as the birth of a child with the disorder.
Carrier Screening Cost: How Much do I have to Pay?
While many service providers offer hundreds of tests, you must understand that how much ever you test, there is always a background risk of from 3% to 5% that your child will have some kind of genetic disorder.
Under such circumstances, you have to keep in mind the carrier screening cost that you will have to pay out of pocket even if your insurance covers part of it.
Many insurance plans pay for genetic screening tests but may offer coverage only for a few tests. Insurance companies usually cover these tests if there is a high risk of genetic disorders, owing to family history or the presence of certain conditions. If you wish to take an expanded carrier screening, it may not be fully covered. You may have to pay anywhere from $100 to over $2000 per person as out-of-pocket expenses even with insurance coverage, depending upon the number and complexity of tests performed. It is advisable to talk to your insurance provider to understand if genetic carrier testing is covered and how much you will spend out of pocket.
At Dreams Fertility, we have designed a one-of-a-kind exclusive financing program with multiple loan plans, including 0% and low-interest terms exclusively for our patients. This program includes the cost of treatment, medication, and testing. We are firm believers in preconception genetic testing and recommend it to all individuals who desire to start a family, and not just our patients who come to us with their infertility struggles. We believe that this is vital information that empowers couples to plan their lives.
As a responsible fertility services provider, we also believe in supporting the many foundations that provide support for certain special medical conditions to individuals and couples. HelpCureHD (www.helpcurehd.com) is a partner foundation that works tirelessly across the globe with the mission to eliminate Huntington’s Disease. We work with the foundation to help patients obtain a PGT-IVF grant to perform genetic testing.
Genetic carrier screening can play a significant role in helping assist your planning to expand your family or continue your life without children. Understanding your genetic carrier status can help you decide whether you want to continue with fertility treatments or pursue an alternative route for bringing children into your homes, such as adoption or fostering.
The recent advances in carrier screening have brought hundreds of genetic disorders, many of which are life-threatening, inside the purview of testing to empower couples with the knowledge to help confidently plan a future with their children.
To know more about how we can help you in your fertility journey, schedule a consult with a Dreams Fertility physician today.
Dr. Luis Murrain joined Dreams Fertility in 2021, providing specialty services in Fertility and Reproductive Genetics. With a shared vision that everyone deserves to have the family of their dreams, we are dedicated to helping all of our patients. We believe that families come in all shapes and sizes, and all of them are beautiful. We are proud to have a long history of providing services to all, including gay, lesbian, and transgender individuals and couples on their road to parenthood.