Preconception Screening And PGD Help Prevent Parents From Passing On Life-Threatening Diseases To Their Children

Source: CBS News – October 26, 2014

A 60 Minutes segment focused on pre-implantation genetic diagnosis (PGD) to help prevention of life-threatening issues to children.

PGD is a test that provides a profile of an embryo to identify known genetic conditions that could be passed from parent to child.

During the PGD process, an embryologist performs a small biopsy of the embryo, and it is sent to a laboratory for genetic screening. Common inherited conditions that PGD screens for are Cystic Fibrosis, Spinal Muscular Atrophy and Fragile X syndrome. PGD can also be used to identify any known genetic condition discovered through preconception screening.

While PGD can be beneficial for patients, the technology has its limitations. Currently, PGD can only identify known single gene disorders—researchers are still discerning how different genes interact to create more complex genetic conditions.

Young patients have a high likelihood of survival after cancer treatment, and are more likely to still be in their childbearing years once in remission. The inability to have a family is a major source of anxiety for many of these patients. It is important for them to have a conversation about fertility preservation options prior to cancer treatment and to be offered the opportunity to make an informed decision.

While some patients may be able to conceive naturally after cancer treatment, this is not a guarantee. Different cancer treatments have varying effects on fertility—some are higher risk than others. Fertility preservation offers patients the opportunity to preserve their gametes before these potentially toxic treatments.

At RADfertility, we offer fertility preservation through cryopreserving (freezing) eggs, sperm or embryos prior to any chemotherapy or radiation. These freezing techniques offer the best chance for success. One can think of cryopreserved eggs or embryos as being frozen in time: the likelihood of pregnancy with them will always be the same as the day they were retrieved. And while the likelihood of pregnancy is always higher when patients preserve their fertility at a younger age, RADfertility will always discuss the likelihood of success using egg and embryo freezing with each individual. Many patients find the likelihood of pregnancy is higher with a frozen embryo or egg preserved prior to treatment, if their ovaries were affected by chemotherapy.

The technology behind cryopreserving eggs and embryos has changed in recent years, leading to significant advancements in vitrification, or flash freezing, techniques. Egg freezing is no longer considered experimental by the American Society for Reproductive Medicine (ASRM), and many offices now have years of experience. However, patients should ask about the length of time a particular lab has been performing egg freezing before choosing a center.

At RADfertility, our laboratory has experience with freezing embryos for over 17 years, and has been freezing eggs since 2008. For patients who cannot use their own eggs, we currently use a frozen donor egg bank—our pregnancy success rates with this bank are over 70%. While these eggs are from young women without infertility, our lab has extensive experience handling these frozen eggs and we have confidence in our ability to successfully freeze, warm and fertilize eggs.

Cancer patients today have many fertility preservation resources available to them, including a consultation with RADfertility prior to chemotherapy and egg, sperm or embryo freezing. Ferring Reproductive Health has a Heart Beat program that offers free fertility medications for patients with a cancer diagnosis prior to any treatment.

For more information and Oncofertility resources, visit our Fertility Preservation page.

Considering PGD for a genetic condition is a very personal and complicated decision. It’s important for couples to understand their risks for having an affected child, along with the benefits and limitations of PGD.

PGD can be used for any known genetic condition found through the family history assessment or identified through carrier screening. If a couple is at high risk for a particular condition, PGD screens each embryo and identifies those which have either a high or a low likelihood of containing the defective gene causing the disease.

We are all carriers of genetic conditions, even with no family history. Fortunately, the likelihood of our partners being a carrier for the same condition is low. However, without routine carrier screening, most couples would have no idea they have an increased risk of having a child affected with a potentially life-threatening genetic condition.

It’s important to understand PGD has limitations. For example, we can only test for known conditions. That is why preconception counseling and preconception screening are very important to identify which conditions a person is at risk for. Even with PGD, we always recommend follow-up confirmation testing during pregnancy.

Preconception genetic screening and PGD may not be the right choice for everyone, but knowing their risks ahead of time can enable couples to make informed decisions when planning their pregnancy.