What not to buy for Christmas

As the shopping season approaches it is tempting to think about novel gifts to buy for friends and family. At this time of year, the purchase of a 'direct to consumer' (DTC) DNA test might be an appealing option for the friend or relative who appears to have everything. Why not give the gift of finding out how much of your ancestry is European or African or Navajo Indian? Or maybe you like the idea of scientifically proving why those salads containing coriander taste so soapy, or someone's caffeine tolerance appears to be so low.

However, I urge you to consider this carefully before buying a DTC DNA test for yourself, a friend or relative.

Some of these tests include the option to reveal medically relevant information. This can range from assessment of risk for late onset multi-factorial conditions, such as Parkinson's disease, to carrier status for recessive conditions, through to cancer susceptibility gene testing – for instance BRAC1/2.

Most of these companies do not offer any access to genetic counselling before or after testing, and precious little education about, or preparation for, the impact of these test results. As a rare breed in the UK – a genetic counsellor in a private clinic – I often find myself seeing patients who have had these types of tests, and picking up the pieces. This is especially true since the NHS clinical genetics services now refuse to accept referrals for patients wanting support post-DTC-test. This is an understandable policy: NHS genetics clinics are understaffed and already at (or beyond) full capacity, with significant waiting lists. It should not fall to the NHS to do the work that private companies are neglecting while making big profits.

In addition, even if suitable education, counselling and pre-test preparation was available before taking these tests, there is a serious problem with what people are getting for their money. The British Society for Genetic Medicine together with the Royal Society of General Practitioners published a position statement in 2019 that is also endorsed by the Association for Genetic Nurses and Counsellors. This points out that 'the analytical validity, sensitivity and clinical utility of such testing may be much lower than is popularly perceived. For certain types of DTC results, there is a very high chance of false positive or false negative results.'

The combination of a lack of pre-test genetic counselling, with the poor clinical information that is generated by these tests, can lead to nasty surprises for consumers. Post-test, those people who do get to see a genetic counsellor will be shocked when they are advised that a repeat test is required (often at significant cost). We know that accreditation standards of DTC laboratories may not be up to clinical standards, and so we will routinely advise confirmatory testing in a clinical laboratory, to confirm that a mutation is genuine, before any action is taken, to make sure the result is not a false positive.

There is also the risk of false negatives because DTC labs are often only screening the most common genes for the most common mutations, and that this can lead to false reassurance. It is possible that a genuine mutation has been missed, either in a gene that hasn't been screened, or even in a gene that was tested, but not for that mutation.

Confirmation of results is especially important if actionable findings are reported. For example, if a cancer susceptibility gene is discovered, such as BRCA1/2, big questions may arise about whether to undergo risk reducing surgery, such as mastectomies. I am aware of one case where the confirmatory test in a clinical lab showed that the BRCA mutation reported by the DTC lab did not exist and was an artefact of the test. It was only down to the diligence of a private breast surgeon that the patient in this case had been referred for genetic counselling prior to risk reducing mastectomy going ahead.

Another area for possible adverse outcomes is if a couple alter their plans for starting a family based on the misleading information given by these tests. One very distressed patient I met recently had concluded that the increased risk of Parkinson's disease given by a DTC test should be a contraindication to having children.

And of course those examples are from the lucky patients who have seen a genetic counsellor to discuss their DTC results. What about the majority who do not manage to access this service?

Aside from the medical implications, there are also the well-publicised concerns about revelations of family secrets, especially the uncovering of misattributed paternity, or the discovery of previously unknown siblings. Some of these stories no doubt have happy endings, and in the case of donor conceived children who are looking for genetic relatives, this can be both sought after and beneficial. However, for those who are taking the test for more frivolous reasons or even just out of curiosity, many apple carts can be upset.

All of this is compounded by the fact that DTC tests in the UK remain largely unregulated. In June 2021 the Science and Technology Committee published its report on DTC genetic testing. Following the publication of this report, the Medicines and Healthcare products Regulatory Agency (MHRA) launched a public consultation, to follow up on some of the regulatory measures suggested by the Science and Technology Committee.

In June 2022 the government response to the MHRA report indicated an intention to finally bring legislation to bear on this industry. This would ensure that clinical standards are required for testing laboratories; oblige companies to provide suitable information and support to customers; and create a risk classification system by which consumers can judge tests. The classification system proposes to classify genetic tests proportionate to their risk, thereby flagging where there is a risk that an erroneous result could lead to a serious adverse event.

However, these proposals are yet to come into force, and in the meantime, it would be fair to say that a DTC DNA test is a very risky Christmas present. Stick with a nice bottle of bubbly, or a Rudolph jumper, to ensure a Merry Christmas and a Happy Festive Season!