Half-hour DNA test to check for killer diseases

A SIMPLE, low-cost DNA test that can reveal a person's chances of developing certain inherited diseases has been developed by scientists in Scotland.

• Dr Juan Diaz-Mochon, from Edinburgh University's school of chemistry, has headed ground-breaking research into the nature of DNA. Picture: Phil Wilkinson

A drop of saliva will be enough to allow medics to pinpoint variations in a patient's genetic code in a test being formulated at Edinburgh University.

It could produce results within 30 minutes.

Tiny changes in DNA can determine whether or not a person is healthy, prone to disease or has a life-threatening condition such as cystic fibrosis. The new test will help identify which patients will benefit from certain drugs for diseases such as cancer, improving survival rates with more personalised treatments.

Health campaigners welcomed the development, which could eventually help the NHS give patients faster and better care. But they said ethical guidelines would have to be in place to make sure patients still had the support to be able to cope with the results.

The test could also be made available in the private sector for those who wished to pay for a personalised health check. Some genetic tests that use different techniques are already available privately.

The new technique can test for genetic variations for one condition at a time, but researchers hope to move on to see if it can be used to decode the whole human genetic make-up.

Dr Juan Diaz-Mochon, from Edinburgh University's school of chemistry, said: "The technology offers a speedy, cost-efficient alternative to existing methods of DNA analysis.

"The market for DNA testing is quickly expanding as it becomes more affordable."

Genetic testing techniques currently use a biological method to look for variations, using expensive enzymes to analyse the DNA. The new method uses a cocktail of chemicals to investigate the genetic material, which is taken from a drop of saliva. Differences or omissions in the DNA code can then show if someone is healthy, susceptible to disease or has a serious condition.

Researchers around the world are constantly finding new genetic clues that show if someone has a higher risk of certain illnesses, such as heart disease, cancer or even bipolar disorder.

The new technology, which has been supported with funding from Scottish Enterprise, will be able to use these new findings to test for the genetic variations.

Dr Diaz-Mochon said using a chemical method to analyse the DNA should end up being quicker and cheaper than current testing methods. "What we have developed is a way of testing chemically," he said. "That means not using enzymes, which are the current method.

"What we have done so far is prove the chemical method. Scientifically, it has been a great achievement."

He said the test could help spot diseases, such as pancreatic cancer, early. It could also indicate if someone had a risk of other diseases, such as heart problems or dementia.

But certain genetic mutations could also tell scientists which treatments a patient who already has cancer would best respond to.

The method, outlined in the journal Angewandte Chemie, could also be used to test for serious genetic conditions such as Huntington's disease and cystic fibrosis.

Current testing to see if someone carries the Huntington's gene can take two weeks to produce results. Dr Diaz-Mochon said: "We could get the results in maybe half an hour from beginning to end. That is what we are aiming for."

Initially, the technique would be made available to researchers, but ultimately he hoped it could be used by health services.

"There is still hard work to do, but the technology is very good and robust," he said. "We know what the technology can do, so it's a matter of getting quicker and making the whole process better."

Currently, the test can look for genetic variations for diseases only one at a time. But the researchers hope the technique could be used to decode the whole human genome, which would give information about genetic variations across the whole spectrum of disease.

Currently, this costs about $50,000 (32,000) and takes five days, but the new technique could see it done for less than $1,000 and in a few hours.

Professor Mark Bradley, who also worked on the project, said: "DNA sequencing is the next step on the pathway for this technology. That is much, much further away.

"We have proved the first part. We can do the single bases (of DNA]. Before we venture into the realm of DNA sequencing, we thought we'd consolidate on this particular offering initially."

The researchers hope to set up a company in the next six months to continue their work. The technology will initially be used by researchers, but could be available in the NHS in the next two years.

Alastair Kent, director of the Genetic Interest Group – a coalition of charities supporting people affected by genetic conditions – said it was a "promising development". The cost of current genetic tests could vary from about 100 to several thousand pounds.

"Anything that allows patients and families at risk from genetic diseases to have access to timely and accurate information about that risk has to be a promising step forward," he said.

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"Some of the current screens used to examine a particular gene don't look for all the possible mutations. If this new technique allows for a more thorough examination of mutations, or a cheaper but reliable method, clearly that is going to be an advantage, because it means people will have access to more high quality information.

"If it delivers the same quality of information, but at a more affordable price, in a resource-constrained environment this has to be an advantage, because more people will be able to benefit."

Ed Yong, of Cancer Research UK, said: "We'll soon reach a point where someone's entire set of genes can be decoded quickly and cheaply, and research like this shows that scientists are getting closer to this goal.

"But getting that information is just part of the challenge – we also need to be able to understand what it means. We're only starting to work out how small genetic differences can affect a person's risk of disease and how they interact with their lifestyles and environments. Eventually, we'll know enough to predict a person's risk of cancer from their gene set, but that's still a long way off."

John Eden, chief executive of the Scottish Huntington's Association, cautioned that counselling and support for those undergoing the test would have to be in place.

A spokeswoman for the Cystic Fibrosis Trust said: "Any new techniques which are cheaper and quicker would be welcomed and this research shows promise for other genetic conditions."

Testing process

• Patient provides a saliva sample to scientists.

• Scientists extract the DNA from the sample.

• The DNA is added to a special cocktail of chemicals.

• The substance is placed into a DNA analysis machine known as a mass spectrometer.

• The machine produces a printout of the results in the form of numbers, each of which link to a different genetic mutation.

• Doctor is given the results and explains the implications to the patient.