Each year, several people resort to sperm or egg donation (called gametes) in order to start a pregnancy. Recently, the Government of Canada issued a guideline to regulate the donation of sperm or ova in assisted reproduction in order to ensure human health and safety. Among these guidelines is the obligation to ensure that the risk of transmission of a genetic disease is reduced.
In the majority of cases, sperm or egg donation is made through a donor bank. In some cases, particularly with egg donation, it may be directed, meaning that the donor and recipient know each other. In recent years, gamete banks have been performing screening tests for hereditary diseases in all their donors. The number of genes tested varies from one bank to another, but this test makes it possible to identify whether the donor is the carrier of certain hereditary diseases. These tests involve genes with autosomal recessive or X-linked inheritance and therefore, the vast majority of these people are unaffected, have no symptoms and are often unaware that they are carriers. However, if your donor is a carrier of a genetic disease and you are a carrier of a pathogenic variant in the same gene, your child will have a 25% (one in four) risk of having this disease or even 50% (1 out of 2) to become a carrier. This is the case, for example, with Cystic Fibrosis, Fragile X Syndrome, Spinal Atrophy and up to 300 other genetic diseases.
People who donate sperm or ova (gametes) can also be tested for carrier diseases. Having this data on your genetic profile in addition to the genetic profile of the donor makes it easier to choose the donor and minimize your risk of conceiving a child with an inherited disease.
It is suggested that you meet with a genetic counselor who will discuss with you the advantages and limitations of this type of test, the different test options (which may include only a few genes or several hundred genes) as well as the possibilities of unexpected results. This meeting allows you to make an informed decision.
With a test prescription from your doctor, the genetic counselor can coordinate the analysis and meet with you again once the results are available to explain those results, the possible implications for you or other family members, and assess the possible risks for your child according to the profile of the donor.
Genetic counseling and screening tests for hereditary diseases play an increasingly important role in assisted reproduction (or assisted procreation) with the use of sperm or ova (gametes) donation.