New test screens for more genetic diseases'This changes everything' - Peter Braude

19 June 2006

A new genetic test could help thousands of women at risk of giving birth to children with diseases such as cystic fibrosis and muscular dystrophy.

Scientists at a conference in Prague are set to reveal the test which will allow doctors to test embryos for many more potential illnesses.

Couples at risk of having children with genetic conditions would, if they wished, then be able to ensure their babies don't have the conditions through screening their embryos and using in vitro fertilisation (IVF).

However, ethical campaigners fear doctors have taken another step towards so-called designer babies. Josephine Quintavalle, from the group Comment on Reproductive Ethics, said the advance was more about killing than curing.

She said:'I am horrified to think of these people sitting in judgment and deciding which embryos should live and which should die. The goalposts are already getting wider and wider.'

Higher chance of diagnosis

The current test, known as pre-implementation genetic diagnosis (PGD), can treat a relatively small number of conditions including Huntingdon's Disease.

But scientists say the chances of diagnosing a disease with the new technique, called pre-implantation genetic haplotyping (PGH), are much higher.

It has been pioneered by scientists at Guy's Hospital in London and looks at the whole DNA of a cell rather than focusing on a specific mutation in one gene, making it quicker to identify diseases in embryos.

'This changes everything'

Peter Braude, Professor of Obstetrics and Gynaecology at King's College London, who works in the assisted conception unit at Guy's Hospital, told the Independent: 'We really think this is a big, big change in terms of what we do. This changes everything.'

Five women in Britain are pregnant with embryos that have been screened with the new technique.

Two of those women are carriers of the defective gene for Duchenne muscular dystrophy. Sufferers are unlikely to survive beyond their teens. Girls can carry the condition without being affected, though not all will inherit the defective gene from their mothers. It is only boys that suffer from the condition's effects.

Prior to the new PGH test, the only option was for the pregnant woman to have a sex test done on her baby and, if the baby was male, to consider aborting it. Now PGH can identify before pregnancy whether the baby would be male or female and, if the baby will be a girl, whether she would be a carrier of the defective gene.