CLINICS could soon be screening embryos for genes that carry a predisposition to breast cancer and other tumours.

The Human Fertilisation and Embryology Authority (HFEA) announced yesterday that it is to consult the public about letting couples choose embryos free from genetic defects. The defects raise the risk of cancer but do not always trigger it.

If the response is favourable, the authority is expected to start approving applications to use the pre-implantation genetic diagnosis (PGD) technique early next year. It may even do so before the consultation is over if urgent licence requests are received.

Several British clinics are ready to offer the test to families with a history of certain cancers, and University College Hospital (UCH), London, has started asking breast cancer patients whether they would be interested in having it.

The review will intensify public debate over the ethics of PGD, used since the early 1990s to allow carriers of genetic conditions such as cystic fibrosis to avoid passing them on. The procedure, which is licensed at ten centres in Britain, involves creating embryos by in-vitro fertilisation, then growing them to the eight-cell stage. One cell is removed and tested for genetic disease, and only unaffected embryos are implanted into the womb.

The authority has previously approved it only for genetic mutations that invariably lead to a disease that is untreatable or strikes in childhood.

Last year, The Times disclosed that the authority had set a precedent by granting UCH a licence to test embryos for a gene called FAP, which triggers bowel cancer when carriers reach their late teens or early twenties. Patients can substantially reduce their risk by having much of their colon removed.

The latest proposal is to allow clinics to screen embryos for genes that are not “fully penetrant”. The consultation, which will start in the autumn, will focus chiefly on the BRCA1 and BRCA2 genes, which raise the risk of a woman contracting breast cancer to between 60 and 80 per cent.

Those who have either gene also have a 40 to 60 per cent chance of developing ovarian cancer. Many women who have one of the BRCA genes, however, do not contract cancer, and those who do generally remain healthy until their thirties. Those who know that they carry either can reduce their risk by 90 per cent by having a preventive mastectomy. Critics argue that allowing embryos to be tested and discarded would pave the way for the “selection of designer babies” for purely social reasons.

Other cancers with a genetic component that will be considered in the review include hereditary non-polyposis colon cancer, neurofibromatosis, a cause of brain and spinal tumours, and retinoblastoma, a cancer of the eye. Such tests are available in the US, Australia, Belgium, France and the Netherlands.

Angela McNab, the authority’s chief executive, said that it wanted a better idea of public opinion before giving its approval for PGD. It was criticised for licensing FAP tests without consulting the public or Parliament.

Ms McNab said: “The question that we want to ask people is, should this technology also be used on diseases that people have a lower chance of getting and may occur later on in life?

“We know that some women with a strong family history of inherited breast cancer choose to have a double mastectomy before they have even developed symptoms to reduce their risk of developing cancer later in life.”

She added: “What we are asking people is whether it is appropriate to use embryo screening technology to stop children being born with faulty genes when there is a chance they may never go on to suffer the cancer.”

Mohammed Taranissi, of the Assisted Reproduction and Gynaecology Centre in London, said: “I would be comfortable offering this to a patient with a BRCA gene, but it is not right just to leave the decision to doctors and patients. It is correct to give wider society some input.”

DETECTABLE DEFECTS

RISKY GENES
BRCA1 & 2
Cancer: Breast, ovarian, prostate. Fewer than 5 per cent of all these cancers are inherited
Prevention: Women, regular mammography or complete removal of breast tissue (prophylactic mastectomy). Research on ovarian screening continuing. Men, prostate screening unproven so not always offered

FAMILIAL ADENOMATOUS POLYPOSIS (FAP)
Cancer: Bowel
Prevention: Surgery to remove bowel, regular screening

HEREDITARY NON-POLYPOSIS COLORECTAL CANCER
Cancer: Bowel, endometrial (women), ovarian (women)
Prevention: Regular colonoscopy, bowel resection surgery and hysterectomy.

Women also have about a 40 per cent risk of developing endometrial cancer and a 10 per cent chance of developing ovarian cancer

NEUROFIBROMATOSIS TYPE 1
Cancer: A range of tumours, mainly brain and spine, but rarely malignant. May cause problems with eyesight or limb weakness
Prevention: Self-monitoring and annual medical check-up

RETINOBLASTOMA
Cancer: Malignant tumour in one or both eyes in babies or young children
Prevention: None. More than 95 per cent of cases can be cured although eyesight is often affected

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