New embryo research sparks fears

The news that thousands of women at risk of giving birth to sick children could benefit from a revolutionary technique to ensure that their babies are free from genetic disorders hit the headlines in Britain last month where the technique was developed. Five women in the country are pregnant after having their embryos tested using the technique, which can screen out the genes for common disorders such as cystic fibrosis and Duchenne muscular dystrophy. The gene for cystic fibrosis is carried by up to one in 25 individuals in some populations and Duchenne muscular dystrophy affects one in every 3,500 male births in Britain. These are just two of more than 1,000 single-gene disorders that could be identified by the technique. Television news bulletins led with the story throughout the day following the announcement by researchers at a meeting in the Czech Republic. And they, and most of the broadsheet newspapers, went into some detail on the novelty of the work and its potential benefits for families. But for others the spectre of 'designer babies' was thought to be the main issue to grab their readers. For about ten years it has been possible to test in vitro fertilisation (IVF) embryos for certain genetic diseases in order to implant only healthy embryos. But this complicated method of pre-implantation genetic diagnosis (PGD) has limitations, according to experts. The new procedure is more accurate, more powerful and marks a radical development in the technology of testing embryos, said Peter Braude, professor of obstetrics and gynaecology at King's College London. " We really think this is a big, big change in terms of what we usually do. This changes everything, it really does, " he said. PGD involves taking a single cell from an IVF embryo and testing the minute quantities of DNA it contains for the presence of a known mutation for genetic disorders such as cystic fibrosis. The new procedure, called pre-implantation genetic haplotyping (PGH), takes a single cell and multiplies its entire genetic complement a million-fold before testing whether the embryo has inherited the defective part of a chromosome from its father or mother. The media reports highlighted the significance of not needing to know the exact genetic details. " It just opens doors to all sorts News focus A paper presented at a conference in Prague led to a flurry of media interest and worries. Nigel Williams reports. of …