Articles

Could your DNA reveal something about your future health?

3 minutes

It’s been over a decade since 23andMe burst onto the scene with a DNA testing kit aimed at consumers. Since then, the market’s blown up, with more of us taking genetic tests last year than in all previous years combined. DNA tests are booming in popularity, but could they tell you something useful about your health?

  • Interest in personal genetics is bigger than ever
  • Direct-to-consumer tests could tell you what’s hidden in your genes
  • Experts aren’t convinced they’ll help you actively manage your health
 
Writing for LV= life insurance, author and science writer Holly Cave (@HollyACave) finds out about DNA testing kits from both sides of the argument.


Jumping on the DNA testing kit bandwagon

Suzi Brooks was intrigued by the idea of knowing more about her genes.

‘My boyfriend and I bought each other DNA testing kits last Christmas,’ she says. ‘Maybe it was naïve, but we thought it would be a bit of fun and might reveal some interesting surprises. It was easy to do – we just had to spit into a test tube, put it in the post and wait.’

Meanwhile, new mum Gina Clarke had a more specific reason for getting her DNA tested earlier this year.

‘For me, it’s part of my ‘get fit year’ – I want to lose three stone of baby weight and feel fab by the end of it,’ she explains. ‘I kicked things off with a body scan and took multiple blood tests as well as a fitness genes test, which gave me a great insight as to what my body looks like, chemically.’


Can home DNA tests really help us understand our health? 

People like Suzi and Gina know from taking their tests that the companies involved aren’t sequencing their entire DNA. Instead, they focus on areas of your DNA where there’s a stronger chance of finding genetic changes that have a clear meaning. 

‘The science is pretty strong,’ says William Newman, professor of translational genomic medicine in The Manchester Centre for Genomic Medicine (@OfficialUoM). ‘A number of genetic variants have been associated with an increased risk of certain common health problems, such as inflammatory bowel disease and high blood pressure.’

But does this mean that the information you’re getting from a home DNA test is going to be useful? Not necessarily. 

‘Where these tests fall down is that these variants individually only account for a very small risk of each of these conditions,’ adds Newman, who is also honorary consultant at Central Manchester University Hospitals NHS Foundation Trust. ‘Many completely healthy people carry these variants and never develop the health problems at all.’

Home DNA kits won’t be able to tell you much about your chances of developing heart disease and most types of cancer, for example. That’s because more complex illnesses like these usually result from multiple genetic changes and environmental effects – including how much you exercise and whether you smoke

But in a few cases, DNA tests can reveal whether you’re at a higher risk of developing diseases such as Alzheimer’s, Parkinson’s and rare conditions like Bloom Syndrome. Suzi was shocked to find out that she had multiple copies of the APOE-e4 gene variations which is often called ‘the Alzheimer’s gene’.

‘Even though my results made it clear that I won’t definitely develop Alzheimer’s, I’m struggling to come to terms with the higher risk of developing a disease that doesn’t have a cure,’ she says, ‘Two of my grandparents had it in old age, but I never really thought seriously about whether it would affect me. Now, the possibility seems very real.’

Gina, whose test focussed on her fitness, found her results useful.

‘There were a few surprises – I don’t have the ‘fat genes’ but I am pre-disposed to be around 3kg heavier than my counterparts. And I have trouble processing sugar so it’s no wonder I ended up with gestational diabetes.’

However, can we rely on the results from a home DNA test kit? A study released in March 2018 raised a red flag, finding that up to 40% of direct-to-consumer genetic tests provide incorrect readings.

Your DNA, your secret?

You might assume that the genetic contents of your spit sample are secret, but that data could be going further than you  might think.

‘Always read the small print,’ says Anna Middleton (@Genomethics), experienced genetic counsellor and head of society and ethics research at Connecting Science, Cambridge. ‘The business model of some home DNA testing companies is actually to sell your DNA data on, and you’d have no say where it might end up.’

On the face of it, DNA testing companies take security and privacy concerns seriously. 23andMe say that they protect customer privacy by using ‘a range of physical, technical, and administrative measures to safeguard personal information’.

In a blog on their website, the company state that they ‘agree that there are some serious issues people should consider before accessing their own genomes’, but that ‘the benefit of giving people access to their own genetic information far outweighs the potential risks.’

‘But we need to be mindful of protecting our DNA,’ adds Anna. ‘It’s our most personal profile, more personal to us than a fingerprint or an iris scan, so think twice before spitting in that tube.’

Can home DNA tests offer peace of mind?

Anna thinks you’re unlikely to find the answers you’re looking for in a home testing kit.
‘They can offer false reassurance and also they can pick up information that isn’t relevant to the question you want answered,’ says Anna.

‘Would I take the test now, knowing what I know?’ asks Suzi Brooks. ‘I’m not sure, but I can’t undo it, can I? I’ve opened a can of worms.’

But Gina Clarke is glad she took the Fitness Genes test.

‘I’m almost two stone down and hoping to feel a lot better by Christmas. I feel like I’m on the right track and my head agrees with my body.’

Gina is not alone: a recent study found that the results of a DNA health test could galvanise people to make a positive change in their health and lifestyle.

Doing a home DNA test can be interesting, but keep in mind that it could turn more serious. If you’re keen to find out more about a particular disease that runs in your family, try chatting to your doctor first. There are lots of different types of genetic tests delivered by genetic medicine departments in hospitals across the UK that can help determine risks of different health problems, guide treatment and provide accurate diagnosis.