A British woman made news earlier this week when doctors reported that they had used in vitro fertilization (IVF) and pre-implantation diagnosis (PGD) to ensure that she would become pregnant with a baby that did not carry a BRCA mutation.
The 27-year-old woman is now about 14 weeks pregnant with a baby girl. Her husband has an extensive family history of breast cancer, and was found to carry the BRCA-1 mutation. According to some media reports, she has a family history of the disease as well.
In an IVF procedure, a woman’s eggs are surgically removed from her ovaries and then combined with sperm in a laboratory dish. One or more embryos are then transferred from the laboratory dish into the woman’s uterus.
Individuals undergoing IVF may be given the option to have PGD, which is also referred to as embryo screening. PGD has been used in the United States for about 15 years to screen for mutations that cause breast, bowel, and eye cancers as well as other diseases. By screening the embryos, doctors are able to ensure that only embryos without a certain genetic condition or chromosomal problem are transferred back into the uterus. The technique is also used to screen for chromosomal problems in couples who have tried IVF repeatedly and failed to become pregnant.
After the British doctors performed IVF, ten embryos developed. PGD found that four of these embryos did not carry the BRCA mutation. Two of these embryos were transferred back into her uterus and the other two were frozen for future use. The six that did test positive for the BRCA mutation were destroyed.
Woman who carry a BRCA mutation have a 50-85% of developing breast cancer. By using PGD to screen for the BRCA mutation, the couple has ensured that their daughter will not carry this particular mutation of the BRCA gene. This doesn’t mean that her risk has been eliminated. Rather, it will be the same as that of any other woman who does not carry the BRCA mutation. Also, we must keep in mind that there are other genes and mutations that we have not yet identified that could increase risk as well as carcinogens in the environment that we cannot control.
As I said on the Today Show, I do not agree with this approach. For one it is an illusion of control. What if the drugs used to develop and harvest the embryos cause cancer? We know that DES, which, in the 1950s was given to women in the first few weeks of pregnancy to prevent miscarriage caused cancers of the vagina in the babies.
We cannot control which genes our children receive nor can we control the unintended consequences of trying to. In addition, this woman is assuming that we will not find a better way to prevent breast cancer in the next thirty years (most hereditary breast cancers do not occur until age 30-50). A lot can happen in thirty years. Think of cancer of the cervix: thirty years ago an abnormal Pap smear meant a hysterectomy because we did not know what caused the disease or how to prevent it. Now we know it is sexually transmitted and caused by a virus and have a vaccine!
Certainly we at the Foundation are working hard on some very promising means for prevention as are many others. I feel strongly that we should not be putting our efforts into eliminating babies with abnormal mutations, who may or may not develop the disease, but rather into eliminating breast cancer all together by finding the cause and how to prevent it.
What do you think? Does PGD just offer parents an illusion of control? Is PGD for the breast cancer mutation a “slippery slope” toward “designer” babies? Is testing an embryo different than testing a fetus for Down syndrome or other chromosomal disorders? If you or your partner carried a BRCA mutation and could afford IVF and PGDâ€”or had it covered by your insuranceâ€”would you do it?