Scientists wonder if knowing what’s in store will leave us better off

WOULD we be better off if we caught a glimpse of our genetic destiny?

Stanford University professor Steve Quake did just that and is still reeling from the consequences.

He is among the less than a dozen people in the world to have his genome – his entire genetic code – mapped and the first one to use it to predict what diseases he might get later in life.

In doing so, he confronted his fears of having inherited a heart condition associated with sudden death. The testing also showed that he has a low 1.4 per cent risk of getting Alzheimer’s disease and more
than 50 per cent chance of developing obsesity, diabetes and coronary artery disease. He also knows now that he has a rare genetic mutation related to heart disease.

So, armed with that knowledge, what did Prof Quake do next? Nothing.

The fit and athletic 40-year-old with no manifest heart problems now is refusing the blood cholesterol-lowering statins that his cardiologist prescribed after studying his genome. He is not even taking baby aspirins which would give him extra protection against a heart attack because he carries a particular gene mutation.

“I’m still thinking about it,” he says.

Prof Quake’s example points to the availability of precise, personalised medicine with side effects that could include relief, heartache and chaos.

He invented a technology that can sequence the entire genome for less than US$50,000 (S$70,000). A team of researchers then probed his genetic data for diseases and the outcome of that exercise was published in the medical journal The Lancet last month.

Using better and cheaper technology in the field of genetic testing can have many implications. Six years ago, it cost about US$300 million to sequence a person’s genome. By last year, it had come down to just US$4,400 and we are now approaching the age of the US$1,000 genome test, deliverable in less than 24 hours, as some California companies are already promising.

Cheaper, faster, more accessible. But for the better? Not necessarily, though it pinpoints the dangers and the cures.

At the outset, there are emotional hurdles to cross. Prof Quake, who received counselling to prepare him for the possibility that the probe might turn up a serious disease, says: “All you hear about when they talk about your genome is ways you’re going to die and get sick... If you’re a worrier, this is not for you.”

There is also no end to the uncertainty of whether you will actually end up with a particular disease you are at risk of getting. Gene testing is still far from being an exact science. Predictive tests deal in probabilities, not certainties.

One person with a given gene may develop disease but another inexplicably will not. A gene may respond to the commands of other genes or be switched on by an environmental factor like sunlight.

There is also the surprising issue of quality control. Genetic tests – without sequencing a person’s full genome – are available today for more than 1,600 conditions. Polls show that Americans believe that
the government regulates genetic tests, but there is actually very little oversight in this area, says Ms Joan Scott, the director of the Johns Hopkins Centre for Genetics and Public Policy.

There is no formal approval procedure a laboratory has to go through before offering a new genetic test. There is no government requirement even that a test must be clinically valid – actually relate to a particular
disease or risk of disease – in order to be sold. So the tests on offer may not be valid, may be performed incorrectly by incompetent laboratories and may be explained inaccurately by physicians.

There is also no forum where a consumer may get an unbiased view about the performance of a test or how meaningful it is.

In fact, hardly anyone has a handle even on how much genetic testing goes on today, whether on a person’s own initiative or ordered by a physician.

“We just don’t know”, is the startling answer from Ms Scott.

In March, United States National Institutes of Health announced that it will establish a voluntary genetic test registry and encourage genetic test providers to share information about the availability and utility
of their tests. A big step but still not mandatory, points out Ms Scott.

But even after the law catches up with technological advances, there is yet another challenge of interpreting the vast quantities of data that will be available.

Mr Hank Greely, the director of Stanford’s Centre for Law and Biosciences, estimates that at least five hours of counselling would be needed to discuss a typical genetic profile. “Who’s going to do that? And who’s going to pay for it?” he asks.

And perhaps the cruellest blow of all – doctors say they cannot be certain they would be treating the patient any differently than before.

For people like Prof Quake, for instance, the only two medicines proven to reduce risk of a first heart attack are aspirin and statins. And a doctor would prescribe them even without knowing his genetic test results.