Gene technology 'sparks revolution'
12:44pm 5th September 2005
Medicine is on the threshold of a revolution driven by the ability to identify faint genetic variations linked to disease, an expert has said.
Until now the technology needed to pin down subtle genetic influences behind cancer and other diseases has lagged behind theoretical science. But new developments that allowed the rapid screening of large numbers of genetic variants in thousands of people were destined to transform medicine, said Professor John Scott.
Prof Scott, a biochemist from Trinity College, Dublin, led a team that discovered two genes linked to spina bifida. Women with the gene variants have a one in 100 chance of giving birth to a baby with the condition. But the risk can be greatly reduced by taking extra folic acid around the time of conception. The genes appear to affect folic acid metabolism, which is why additional supplements of the vitamin are beneficial.
Such gene variants are not like the easily identified rare defects which give rise to severe diseases such as haemophilia and cystic fibrosis. They are relatively common differences in DNA which nonetheless can alter the risk of birth defects, cancer or other conditions.
The now completed blueprint of human DNA, the human genome, will in future allow the rapid identification of these variants, said Prof Scott. "What we'll see is a new emerging area where the science has been done and the technology has caught up," he said on the first day of the BA Festival of Science taking place at Trinity College.
"We can now look at thousands of variants in thousands of people at the same time." The latest technology was capable of simultaneously identifying 1,500 gene variants in 2,000 people, he said.
"One might perhaps be surprised that there hasn't been more made of this issue," he added. "The reason is that the technology hasn't caught up until now." Subtle genetic variations may explain why only some people will get lung cancer from smoking, he said.
Looking ahead, he expected the technology to bring major changes in medicine. "That black box your GP is looking into when he asks about your family history will now be understood," said Prof Scott. "He'll be able to ask whether you have polymorphisms that predispose you to colon cancer. He'll be able to say that definitely you should have a coloscopy because you're at very high risk, and so should your siblings and close relatives.
"There's also the question of when the variants identified indicate something preventable. For instance, does fibre have some preventable effect with colon cancer, perhaps only in certain people.
"Subsequently there's the whole question of treatment. The whole business of why some drugs work on some people better than others is almost certainly related to genetics."
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