Each gene in our cells tells our body a specific message on how to grow and develop. Genetics can influence a person’s hair colour, eye colour, and personality. For some, family planning can be an exciting time to see which genes are passed on to future generations. However, for other families, potential parents might be worried about the chances of passing down a genetic condition which affects a child’s health or quality of life.
This week is Jeans for Genes—a week dedicated to raise awareness for individuals and families affected by genetic conditions. This blog talks about how we can talk to you about your genes at Care Fertility, and what it could mean for your fertility treatment.
What if I have never had genetic testing?
Some people are not aware of a family history of a genetic condition, but are interested in learning more about their genetic background before having a family. They might be interested in a type of test called “expanded carrier screening.”
In expanded carrier screening, an individual or couple has a genetic test to look for changes in genes which can be passed on. These conditions can be inherited in different ways:
- Autosomal Recessive—this means that both people in a couple must be carriers of the same condition in order to have a child affected by the condition. If both potential parents are carriers, there is a 1 in 4 (25%) chance their child will be affected.
- Autosomal Dominant—this means that only one person in the couple needs to carry the genetic factor in order to have an affected child. If one parent is a carrier, there is a 1 in 2 (50%) chance their child will be affected.
- X-Linked—if the female partner is a carrier of an X-linked condition, there is a 1 in 2 (50%) chance she could pass it on to her child. Usually, boys have more symptoms of X-linked conditions than girls. If the male partner has an X-linked condition, he passes it on to all of his daughters and none of his sons.
Most people are carriers of a few autosomal recessive genetic conditions, but since they are rare, it is relatively uncommon for both individuals in a coupleship to carry the same condition. However, the implications for carrying a genetic condition can be significant. Care Fertility has an experienced team of genetic specialists who can talk to you about your results, and to help you decide what to do with that information.
For families who know there is a genetic condition in the family, whether through expanded carrier screening or due to their family history, Preimplantation Genetic Testing, or PGT, might be an option for them.
What is PGT-M/SR?
In PGT, embryos are screened for a specific condition affecting a specific gene (“Monogenic”) or the size and shape of one or more chromosomes (“Structural Rearrangements”). Together, this technology is known as PGT-M/SR.
Individuals or couples are under the care of our specialist team of genetic experts, fertility doctors, nurses, and embryologists. A specialist test is designed which is usually unique to your family. Once all of the genetic and fertility work-up is complete, the female partner (or egg donor) will undergo fertility treatment similar to other forms of in vitro fertilisation, or IVF. The male partner (or sperm donor) provides a sperm sample, and the eggs are fertilised in the laboratory. Once an embryo is around five or six days old, a few cells are safely removed, and genetically tested for the condition in your family. The numbers of chromosomes are also checked in a process called PGT-Aneuploidy, or PGT-A.
The results usually take around a month. Any healthy and unaffected embryos can then be placed into the female partner’s womb (or the surrogate) one at a time until a pregnancy occurs.
More information about PGT-M/SR, including how to be referred, can be found here.
What else can genetic counsellors do?
We also appreciate the decisions around genetic testing can emotionally challenging, so our genetic counsellor will help make sure you feel supported throughout your journey. As genetic counsellors have training in psychological support as well as the science of heritable conditions, they have an idea of how you might be feeling during your treatment. They can help guide you through the many decisions that might need to be made around genetic testing in a non-judgemental, non-directive way.