Personalised genetic testing is gaining popularity, but the area is poorly regulated - what do consumers need to know? Claire O'Connellfinds the answers
IT'S THE ultimate in techie navel-gazing - knowing your own genetic code. And with private companies offering personalised DNA screening for under €700, it's within the reach of the consumer.
But getting a readout of your code is one thing. What it means for your future health is quite another, and that relationship is still poorly understood.
And as health authorities in the US start to clamp down on direct-to-consumer genetic testing kits, experts warn that consumers need to be vigilant if they want to have their DNA screened, and realise there could be future implications.
One of the highest-profile players in the new field of personalised genetic testing is 23andMe in Mountain View, California. Late last year it launched its screening service. You apply online, the company posts you out a kit, you mail back a cheek swab, the company screens your DNA for interesting hotspots of genetic variation called SNPs, then gives you a private, web-based readout of what your results mean.
"It has been really popular and we get a lot of really good feedback," says Dr Brian Naughton, founding RD architect at 23andMe, who graduated from Trinity College Dublin before doing a PhD in the US.
Backed by Google, the company is well-resourced and the user-friendly website lists scores of SNPs and links with information about the latest research.
It's all a bit of fun to find out whether you have the SNP for wet earwax or tasting the bitter qualities of Brussels sprouts. Or maybe you want to get a different view of your ancestry. And among the community of 23andMe users, there's even a bit of light-hearted competitiveness over one SNP linked with improved running speed, according to Naughton.
However, things get more ominous if SNPs are linked to the risk of developing early-onset Alzheimer's, obesity, heart disease or multiple sclerosis, and critics have voiced concerns over people being worried if they learn about a genetic predisposition to a disease, or abandoning healthy practices if they see their DNA codes for a healthy heart.
But genes are just instructions; it is how they get used that matters. And we have only started to scratch the surface of how our environment regulates how genes are turned on and off. So what can a readout of SNPs really tell us about our future health? "Genes are not the be all and end all," says Naughton. "We do struggle with that and we try to be as upfront as possible, reiterate that this isn't everything, there's more to it. Having a low risk for diabetes, according to your genetics, does not mean that if you are obese you will not get diabetes."
And if a client is worried about a result, the advice from 23andMe is to speak with a doctor. But health authorities in New York and California are waking up to the need to regulate. They recently slapped "cease and desist" letters on a number of companies, including 23andMe, asking them to stop offering genetic screening directly to the public in the absence of a medical referral.
Despite this, 23andMe has reportedly chosen to keep supplying clients with tests.
"In general, the philosophy of the company is that we don't want to be the one telling you what you can and can't know about your own body, your own DNA," says Naughton.
That said, they are in favour of regulation, according to 23andMe's communications manager, Rachel Cohen. "We think we are a responsible company, and we try to explain the limits of genetic research today, and what the information we are giving you means.
"We worry that not all companies are taking that as seriously as we are, so we would welcome some sort of common standard," she says, describing 23andMe's service as "more informative than diagnostic".
But getting a readout of SNPs isn't even that informative, because we don't know enough yet about how genes interact with the environment, according to barrister-at-law Asim Sheikh, who lectures in legal medicine at University College Dublin.
He warns that consumers need to be aware of what exactly they are getting when they order a genetic screen, and that companies need to declare clearly whether the information is accurate and meant to have medical or therapeutic use.
"There's an onus on the trader to provide specific information so the consumer knows what its fitness for purpose is. That becomes very relevant to this kind of genetic testing kit," he says. "The consumer cannot be misled into thinking this might be a medical service."
There is also the question of what happens to the swab sample after it has been used. Consumers should find out whether the company stores them after analysis (samples sent to 23andMe are destroyed), because they could later potentially be used for other tests in the future, warns Sheikh, who is vice-chair of the Irish Council for Bioethics.
In addition, having a genetic screen with believed medical implications could later come back to bite consumers here, he adds: "If I have decided of my own accord to do a [genetic] test, and I'm filling out my life insurance, on the form you have to sign that you have disclosed all risks.
"If you think you have information in your possession which has a bearing on the risk, you must disclose that. Then if the insurance company thinks it's a serious risk they will either refuse me, or my premium will be higher." Sheikh believes that government agencies should move sooner rather than later to ensure that consumers are aware of the issues around personalised genetic testing. "There's no point in waiting five years for thousands of consumers to have spent a lot of money and be very worried about their results and security after the fact," he says.
"It's not an issue of scaremongering - it's about providing choice. Consumers are free to say 'I have the money, I'd love to have this done', it's no different to getting your horoscope," says Sheikh. "And if you have all the information and all the caveats, you are entitled to do whatever you want. But if people haven't thought about these issues, then they should."
Genetic hotspots: a snip off the old block
It may be a little disappointing to find out that, genetically, all humans are almost 99.9 per cent the same.
What distinguishes you from me - and from everyone else on the planet - is down to tiny changes called single-nucleotide polymorphisms (SNPs or "snips"), dotted along your DNA.
Of the roughly three billion "letters" in each individual's genetic code, SNPs account for only around 10 million. But, by zoning in on those hotspots, scientists can get a quick handle on your genetics.
So rather than sequencing your entire code, which would be laborious and expensive, companies like 23andMe isolate your DNA from a cheek swab, then wash it over a prepared chip that screens about half a million SNPs of note.
Then they link your resulting profile with risk assessments and available scientific information and present it through a web portal for you to peruse, and share the information with others if you wish.