All you need to know about the donor’s Genetic Matching
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What is the donor’s genetic matching?
Genetic matching, or genetic paring is the study of genetic data between donor and recipient to ensure genetic compatibility between them in terms of avoiding transmission of a recessive disease. In this process, the egg or sperm donors selected do not share pathogenic variants in the same genes with the recipients in order to minimise the risk of genetic diseases and improve the chances of success of the assisted reproduction treatment, understanding success as the birth of a healthy newborn.
Importance of genetic diversity in fertility treatments.
In the process of selecting egg or sperm donors, genetic tests are carried out to minimise the risk of transmitting genetic diseases to the future child, as well as to ensure the assisted reproduction treatments efficacy and success. Thus, genetic diversity is key in fertility treatments to reduce the risk of both parents carrying the same recessive mutation, and therefore avoid recessive diseases.
How are the donors and receptors evaluated at Instituto Bernabeu?
The evaluation of donors and recipients at Instituto Bernabeu is a process that ensures the health and safety of all parties involved, as well as the treatment success.
Genetic analysis
Autosomal recessive inherited diseases have a low prevalence in the population (1% of all newborns), but are often serious diseases. The vast majority of people are healthy carriers of some recessive disease.
To avoid this, Instituto Bernabeu performs the Genetic Compatibility Test (GCT) on donors and recipients. The GCT is a carriers genetic study to identify mutations in the genes responsible for recessive and X-linked diseases. The study of this massive DNA sequencing panel makes it possible to detect carriers of recessive genetic diseases.
Comparison of genetic profiles
In the recessive disease donor cross-matching test, the genetic data of the donor and recipient are compared to ensure they are not carriers of the same recessive diseases, which would reduce the risk of the future child inheriting those recessive diseases.
In recessive diseases, people who have only one copy of the mutated gene (carriers) do not develop the disease, as both copies of the gene must be mutated (carriers of the disease) in order to develop the disease. Consequently, when both parents are carriers of the same disease, there is a 25% probability that the children will inherit both mutated copies and consequently suffer from the disease.
Compatible donor selection
In the selection of donors, medical and family history is assessed to identify possible genetic or hereditary diseases. A psychological evaluation (psychosocial and ethical aspects) is carried out, ensuring that the donor understands the process implications and is emotionally prepared to participate.
There are a number of considerations in the criteria for selecting a donor for a particular couple. In addition to blood group and phenotypic traits, the donor is assigned a genetically compatible donor, i.e. one who does not have mutated genes in common with the patient. At Instituto Bernabeu we choose donors whose genetic profiles are compatible with the parents, minimising the risk of transmitting genetic diseases.
Benefits of genetic matching
Increased chances of success in IVF treatments
By selecting genetically compatible donors, the likelihood of successful fertility treatments is improved by maximising the chances of a healthy child.
Reduced risk of genetic diseases in offspring
By carrying out a genetic analysis of donors and recipients, we are preventing they are both carriers of the same mutation, which significantly reduces the risk of transmission of hereditary diseases in offspring. It is estimated that after genetic compatibility testing, the risk of the birth of an affected child is reduced from 0.5-1 in 100 to 1 in 40,000 – 50,000 births.
Increased likelihood of a healthy pregnancy and a healthy baby
Genetic compatibility between donors and recipients can increase the likelihood of births of healthy children free of recessive diseases.
Improved donor selection for healthy offspring with desired characteristics
By comprehensive genetic matching, through rigorous genetic evaluations and careful donor selection, Instituto Bernabeu’s professionals can prevent congenital anomalies and other developmental problems that could arise from unfavourable genetic combinations.
Genetic test limitations
In this genetic test, the regions of analysis studied are only the X-linked and recessively inherited genes included in the panel. It focuses on known and catalogued mutations, but there are many genetic mutations that have not yet been identified, are not reported in current databases or are outside the region tested, which may limit the ability of the tests to predict all genetic risks.
Genetic testing can be expensive, which may limit access to these technologies for some couples seeking fertility treatment. The price of genetic matching may vary depending on the clinic performing the test and the number of genes included, which will reduce the risk of more or fewer diseases.
Genetic information may generate anxiety and stress for prospective parents, especially if mutations or potential risks are identified. The emotional burden of these findings can be significant and requires appropriate genetic counselling.
Genetic Matching also for couples
Genetic matching is not only relevant for donors and recipients in fertility treatments, but also for couples seeking to conceive naturally or through assisted reproduction techniques.
Genetic counsellors interpret the results of Genetic Matching and advise the couple on the reproductive options available and the associated risks in cases where both parents carry mutations in the same gene, and have a 25% chance of having a child with a recessive disease.
In in vitro fertilisation treatments, Preimplantation Genetic Diagnosis (PGD) can be performed in couples in which both are carriers of recessive gene mutations for a certain disease. PGD (PGT-M) of the embryos before they are transferred guarantees that the embryos to be transferred are not carriers of those genetic diseases shared by their parents.
At Instituto Bernabeu we recommend to take the genetic compatibility test to:
- Couples who start looking for a pregnancy by natural means or through assisted reproduction treatment with their own gametes, especially if the partners have a family history or are carriers of a genetic disease.
- Couples who are related to each other (consanguinity) because they will have a higher risk of sharing mutations in the same gene.
- Couples undergoing assisted reproduction treatment involving donor gametes (oocytes or sperm).
Sources:
- American Society for Reproductive Medicine (ASRM)
- National Institutes of Health (NIH)
- Centers for Disease Control and Prevention (CDC)
- Genetics Society of America (GSA)
- European Society of Human Reproduction and Embryology (ESHRE)
Paqui Lozano, molecular and genetics biologist at Instituto Bernabeu