Preimplantation Genetic Testing (formerly Preimplantation Genetic Diagnosis) for BRCA Mutation Carriers

Preimplantation Genetic Testing (PGT) is a new medical term first published in the 2017 edition of the International Glossary on Infertility and Fertility Care that replaces both the terms preimplantation genetic diagnosis (PGD) and preimplantation genetic screening (PGS).

PGT refers to all types of genetic testing on embryos. All PGT requires:

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  in vitro fertilization (IVF)

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  embryo biopsy

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  genetic testing on the biopsied sample

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  transfer of selected embryos into the uterus, depending on the genetic testing results 

It’s natural for people with a gene mutation linked to hereditary cancer to feel concerned about passing the gene mutation on to their children. If you have one of these genetic mutations, each of your children has a 50% chance of inheriting it.

Some people of childbearing age choose to use PGT to prevent passing an abnormal gene mutation to their children. Traditionally, people have used PGT to avoid passing along hereditary diseases such as muscular dystrophy and Huntington’s disease. But people also use PGT to prevent passing on any cancer-related gene mutations — particularly the more common mutations in the BRCA1 and BRCA2 genes.

PGT can offer parents and their future children peace of mind, but it does involve a lot of time, effort, and expense. 

The first step is going through the IVF process. With IVF, a woman takes medications that stimulate her ovaries to produce multiple eggs. The eggs are removed and fertilized outside the body in a test tube. Successfully fertilized eggs then become embryos.

After a few days, the embryos are ready for the PGT procedure. About five cells are removed from each embryo to be tested for genetic conditions that the parents have a high risk of passing on, including, for example, a BRCA1 or BRCA2 mutation. The parent can then choose to have embryos without a BRCA mutation implanted in the uterus or stored for future use.

IVF isn’t always successful, however. Sometimes no embryos form, or all the embryos that form test positive for the mutation. Furthermore, embryos implanted in the uterus don’t always result in pregnancy. So you may need multiple cycles of IVF and PGT over time.

Costs for IVF and PGT can range widely and cost thousands of dollars per cycle. Although health insurance plans may offer some coverage in selected cases, the costs of multiple cycles can add up quickly. Costs can be even higher if the gene mutation you are screening for is very rare. 

If you’re considering PGT, talk to your genetic counselor and a fertility specialist. They can help you weigh the pros and cons of your situation. Some people who want to have children find that they need to have IVF anyway — either because they’re having trouble getting pregnant, or they want to store eggs or embryos to use after they complete their cancer treatments. Adding PGT for the BRCA1 or BRCA2 mutation may make sense in these cases.

Some people feel that — despite their concerns about their future children’s health — PGT is simply not worth it or not affordable. It may comfort some people who can’t or won’t consider PGT to know that children have a 50-50 chance of not inheriting the mutation.

PGT is controversial. When it comes to BRCA mutations, some people may be concerned about the following:

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  A BRCA mutation is not a disease. It’s a risk factor for adult-onset cancer, and there are other ways for someone with a mutation to significantly lower cancer risk later in life.

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  Selecting mutation-free embryos doesn’t guarantee that offspring remain cancer-free during their lifetime.

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  Some people have ethical concerns about destroying embryos that carry a genetic mutation. They also worry about parents selecting for other traits such as gender.