Is genetic diagnosis of breast cancer genes suitable before embryo implantation?

This paper studied how suitable preimplantation genetic diagnosis was for patients who had mutations of the breast cancer 1 or 2 (BRCA1 or BRCA2) gene. 

Hereditary breast and ovarian cancer (can be passed down from parent to child) are caused by mutations in genes called breast cancer 1 (BRCA1) and breast cancer 2 (BRCA2). Carriers (people who have the mutated gene) of BRCA1 or BRCA2 have an increased risk of breast cancer. Parents who have this mutation have a 50% risk of passing on this mutation to their offspring. One way to avoid this is through preimplantation genetic diagnosis. After the egg is fertilized in vitro (outside of body), the embryo is tested for breast cancer gene mutation. Embryos without the mutation are then transferred into the uterus. 

Patients were screened for the presence of BRCA1 or BRCA2 mutation. Male carriers, female carriers with no sign of breast cancer and breast cancer survivors were eligible for the study. 70 couples underwent preimplantation genetic diagnosis.  

After in-vitro fertilization, embryos were analysed for presence of the mutation. They were classified as affected (mutation present), unaffected (mutation absent), abnormal (abnormal gene) or no diagnosis (inconclusive results). Embryos without the mutation were then transferred into the uterus. Women were followed up on their pregnancy outcome.

In one couple, both male and female partner had a BRCA1 mutation. Of the 71 patients who had the mutation, 59.2% were female. 26.2% of these female carriers had undergone breast surgery before the programme and 14.3% had a history of breast cancer.

Of 720 embryos tested for the mutation, 40.8% were unaffected, 43.2% were affected, 9.7% were abnormal and 6.3% had no diagnosis. In 61.3% of in-vitro fertilization cycles, 23.9% resulted in clinical pregnancies. Overall, of 41 children, 38 children were born alive. Two female carriers of BRCA1 were diagnosed with breast cancer after ovarian stimulation for in-vitro fertilisation.

The authors concluded that preimplantation genetic diagnosis for hereditary breast and ovarian cancer is a suitable technique with good reproductive outcome. 

There was a small sample size. Larger studies are warranted. Further studies need to be done on the safety of this procedure. 

If you have BRCA1 or BRCA2 mutation, talk to you doctor about undergoing preimplantation genetic diagnosis.