New genetic testing technologies can provide patients with information regarding options that may help with the success of the treatment and reduce the chances of having a child with a certain genetic condition. The available options (if applicable to your case) and their individual merits will be discussed with you during your consultation.
Preimplantation genetic screening (PGS or PGT-A)
PGS (also known as aneuploidy screening) involves checking the number of chromosomes in embryos. Embryos with abnormal chromosome arrangements often result in a failed treatment, miscarriage or the child may have an abnormal genetic condition (like Down’s syndrome). During PGS, a small number of cells are removed from the embryos. The DNA of these cells is then tested to see whether they have any chromosomal abnormalities. Only embryos without chromosomal abnormalities are placed back in the womb.
Preimplantation genetic diagnosis (PGD or PGT-M)
PGD is a type of embryo testing that can be beneficial for people with serious inherited conditions. During PGD, a small number of cells are removed from the embryos. The DNA of these cells is then tested and only embryos free of the condition are placed back into the woman’s womb
PGD with haplotype testing is a form of embryo testing which can be helpful in the treatment of children with life-limiting blood disorders who need an exact tissue match for their treatment. Where there isn’t an exact tissue match within the family, it’s possible to undergo IVF and test embryos for an exact tissue match.
Extended carrier screening
Carrier screening tests can determine whether you or your partner are a carrier for certain genetic diseases. If both you and your partner are carriers for the same disease, although as you have two copies of each gene you will not be affected, there would be a 25% chance that the embryo may inherit one faulty gene from each parent and have the disease. This test looks at the odds of this occurring so that embryos can be tested by PGD if there is a risk.
Extended carrier screening for treatment with donor eggs and sperm
Many donor egg and sperm banks now provide extended carrier screening results for their donors. Most people are carriers for one or more genetic diseases. You may wish to have carrier screening to check that you do not carry the same genetic disease as your donor to reduce the risk of having an affected child.
Genetic counselling will be recommended if you are considering chromosomal or genetic screening of your embryos, or to discuss the results of carrier screening. The counselling can be helpful in planning and taking an active role in decision-making about your treatment, especially if you have a personal or family history of a genetic disease or you are known to be a carrier of a genetic disorder or chromosomal condition.