A woman has conceived Britain’s first baby guaranteed to be free from hereditary breast cancer.
Doctors screened out from the woman’s embryos an inherited gene that would have left the baby with a greater than 50% chance of developing the cancer.
The woman decided to have her embryos screened because her husband had tested positive for the gene and his sister, mother, grandmother and cousin have all had the cancer.
The couple produced 11 embryos, of which five were found to be free from the gene. Two of these were implanted in the woman’s womb and she is now 14 weeks pregnant.
By screening out embryos carrying the gene, called BRCA-1, the couple, from London, will eliminate the hereditary disease from their lineage.
About 5% of the 44,000 cases of breast cancer diagnosed in Britain each year are estimated to be caused by the BRCA-1 and BRCA-2 genes, both of which can be detected in embryos.
Doctors say thousands of cases of breast cancer could be avoided by screening embryos using the technique called preimplantation diagnosis (PGD).
Many women who test positive for the gene have their breasts surgically removed to avoid the disease. Only one other woman – an Israeli mother-to-be – is thought to have become pregnant after undergoing the embryo screening.
The 27-year-old British mother, who asked not to be named, says that after seeing all her husband’s female relatives suffer from breast cancer, she felt she had to take action to save their children from the same plight. Any daughter born with the gene would have had a 50% to 85% chance of developing breast cancer.
She said: “For the past three generations, every single woman in my husband’s family has had breast cancer, as early as 27 and 29. We felt that, if there was a possibility of eliminating this for our children, then that was a route we had to go down.
“It has been successful for us which means we are eliminating the gene from our line.
“We had been through his sister being ill, so it was something we had seen first hand. I thought this was something I had to try because, if we had a daughter with the gene, and she was ill, I couldn’t look her in the face and say I didn’t try.”
The woman and her 28-year-old husband had to go through IVF (in vitro fertilisation) even though they are fertile, in order to create embryos that could be screened.
Tests on the 11 embryos were conducted by removing just one cell when they were three days old. Six of the embryos carried the breast cancer gene. Two embryos that were free of the gene were then implanted, resulting in a single pregnancy.
The couple have also been able to freeze two healthy embryos for future use.
The woman said she felt a responsibility to put herself through the invasive IVF procedure. “The treatment I had to go through was nothing in comparison to what I have seen members of my husband’s family go through.”
In addition to breast cancer, women carrying the gene also have a higher risk of ovarian cancer and male carriers are at greater risk of developing prostate cancer.
The couple’s doctor, Paul Serhal, medical director of the Assisted Conception Unit at University College London hospital, said the breakthrough gives parents the option of avoiding passing a high risk of breast cancer on to their children.
He said: “Women now have the option of having this treatment to avoid the potential guilty feeling of passing on this genetic abnormality to a child. This gives us the chance to eradicate this problem in families.” Serhal added: “It may be devastating psychologically and emotionally for a young woman to have her breasts removed.”
Serhal has treated other couples to create babies free from less well known cancer genes, including one that causes eye cancer and another that carries a high risk of bowel cancer.
Some critics say it is wrong to destroy embryos because there is only a chance women with the gene may develop breast cancer in adulthood. They argue that, increasingly, breast cancer can also be successfully treated.
