http://news.bbc.co.uk/2/hi/health/7121026.stm
*Can a gene test predict the future?*
By Emma Wilkinson
Health reporter, BBC News
*Scientists say they are beginning to make real progress in pinning down the
genetic basis of common diseases.*
In the past six months alone there have been reports of key genes involved
in diabetes, heart disease, bowel and breast cancer, dementia and obesity.
And subsequently there has been an explosion of companies offering gene
tests to predict a person's future risk of life-threatening disease.
But how useful are such tests and could they do more harm than good?
Christine Patch, consultant genetic counsellor at Guys Hospital in London
and member of the Human Genetics Commission, believes the science is not yet
strong enough to support the multiple gene tests on the market.
"You're wasting your money," she said, adding that such tests were not
without disadvantages.
"The risk is the anxiety caused by saying someone is a high risk.
"I also think there's a risk of false reassurance - if you tell someone they
are at low risk of heart disease that may cause someone to continue drinking
alcohol and eating saturated fats."
The commission is due to publish a report on Tuesday calling for tighter
controls on tests to make sure they are based on sound evidence and not
making unsubstantiated claims.
In a previous report, they recommended that predictive genetic tests should
only be available via a consultation with a doctor and, like prescription
medicines, should not be advertised directly to the public.
Dr Patch said many tests will not tell an individual anything more than they
would know from just looking at their family history.
"We wouldn't use these tests on the NHS, where we have to get value for
money," she said.
*Common diseases*
Many companies in the US and Europe offer gene tests for conditions such as
diabetes, heart disease and cancer.
And others are coming on the market that scan all 500,000 genetic variants
to give an individual a picture of their risk of several diseases at once.
Dr Paul Jenkins, consultant endocrinologist and clinical director of Genetic
Health - a UK company offering a variety of tests - said it was an evolving
field.
"But we believe the science is strong enough to offer individuals broad risk
assessment of their genetic predisposition to many of our common age related
diseases.
"In order to avoid inappropriate anxiety or concerns we ensure all of our
clients receive a medical consultation with a consultant to put their
genetic results into context."
The company also said they turn away clients with unrealistic expectations
and would encourage more regulation of tests.
Dr Paul Pharoah, senior clinical research fellow at Cambridge University
Cancer Centre, said such tests were not yet clinically meaningful.
"The science is at the preliminary stage, we only know about a handful of
genes.
"The number of companies [offering tests] has gone up rapidly in the past 12
months because we are starting to find genes that are really associated with
disease.
"But the likelihood is there's hundreds of genes for every disease.
"To start counselling people about their risk and how they should modify
their lifestyle to modify that risk is effectively ludicrous. It's not good
science."
Stuart Hogarth, from the Institute of Science and Society at University of
Nottingham, has spent the past few years looking into how such tests are
regulated.
He said there were not enough controls in place to ensure people were not
being misled.
"We still do not have the regulatory framework. We haven't developed any
standards to indicate to companies what kind of data is needed before they
bring something to market."
Such tests are covered by an EU directive but because they are deemed low
risk, they are not subject to a review before they are marketed.
This means there is no obligation for companies to provide evidence to
support the claims they make, he explains.
Many experts, including the Human Genetics Commission, think the genetic
tests should be classified as higher risk meaning they would be subject to
greater controls.
"We have no way for consumers to separate good tests from bad tests and
there is a severe danger of losing public confidence - all that's left is
we're asking consumers to be sceptical.
"But some companies are doing a much better job than others," he said.
He added that in the past year researchers have made real progress in the
science but more research was needed.
*Public confidence*
Professor Shirley Hodgson, an expert in cancer genetics at St George's
University of London, stressed there are very useful genetic tests such as
the BRAC1 test for breast cancer.
"I wouldn't want people to devalue these tests because we are throwing these
relatively low value tests at them."
She added that people needed proper genetic counselling in order to process
the results.
One man she had seen in her NHS clinic had been incredibly anxious after
paying for a test which suggested he had an increased risk of a variety of
cancers.
"I didn't think his genotype was important but he was in a state of
collapse.
"The other thing was it had left him with very little he could do."
One of the main concerns of those who work as genetic counsellors is that
people need to fully understand what the risk means.
Especially as we know so little about the link between environment,
lifestyle and genes.
Dr Pharoah said a more realistic use for gene tests would be to lower the
age at which someone was screened for breast or colon cancer.
"We're almost there for these diseases but these are very specific
examples."
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