Tuesday April 21 2009
The NHS provides around 300 proven DNA tests
“Private health checks can be a rip-off,” reported The Sun. It explained that expensive “body MOTs” can do more harm than good and throw up false results so people have unnecessary treatment. It reported that the Nuffield Council on Bioethics claims some techniques such as CT scans have radiation risks that increase the likelihood of cancer.
Widespread press coverage has been given to news that the council says there is a rise in the use of online drug sales, private DNA tests and scans in recent years, and more regulation may be needed. The council has launched a consultation to discuss the issues and wants to hear people's opinions on the ethical issues surrounding commercial medical profiling companies.
The NHS provides around 300 proven DNA tests for single gene disorders such as Huntington's disease and cystic fibrosis. However, private companies claim to offer DNA profiling for complex conditions such as heart disease and cancer, which can have numerous causes.
Genetic profiling is still a relatively new technology and different companies can return varying test results. Body imaging can also potentially be harmful and cause undue alarm or even give false reassurance. If you want to take part in the consultation visit the Nuffield Council on Bioethics website.
Who has given this warning?
This warning originated from the Nuffield Council on Bioethics. It is an independent body, funded jointly by the Nuffield Foundation, the Medical Research Council and the Wellcome Trust. The council have begun a consultation to discuss commercial medical profiling and online medicine.
What will the consultation look at?
The council has brought together leading experts to look at ethical, legal, social and economic issues that arise in the application of new health and medical technologies. It will focus on new technologies that aim to deliver highly individualised diagnostic and other services. Any responses to the consultation are due by 21 July 2009 and a report setting out the council’s findings will be published in spring 2010.
The working party includes scientists, social scientists, lawyers and philosophers. It will consider whether there should be tighter regulation for genetic tests and whether people who buy them and then consult their GPs about the results, should have to pay for such follow-up advice.
The council wants to hear the views from a wide range of people on the ethical issues raised by these commercial medical profiling technologies. It is also interested in online healthcare, such as buying drugs over the internet, and telemedicine, which includes things like having consultations with specialists by video conference. These technologies and services are increasingly focused on the individual and often mean that the GP is no longer involved in healthcare.
Which health checks are being warned of?
The authors of the report say that “recent technological developments, new political and economic priorities, and the widespread drive towards patient-centred care have led to increasingly personalised health care services, with a strong focus on prediction and prevention.” They specifically mention DNA profiling and body imaging as examples of these services.
DNA profiles aim to predict a person’s risk of developing a range of diseases. They usually involve sending a saliva sample by post to a testing centre, where the DNA is extracted from cells in the sample and tested. These tests record and highlight variants in the genetic sequence, known as Single Nucleotide Polymorphisms (SNPs). The presence or absence of particular risk associated SNPs can then be used in a statistical model to calculate a persons genetic risk.
Some companies offer to analyse the entire genome (a person’s entire genetic code). DNA profiling can be bought over the internet for fees ranging from £250 to £800 and many require no genetic counselling or medical supervision.
The private companies then alert patients to their inherited susceptibility to conditions including heart disease and cancer. Clients can usually access the results by logging on to protected sections of the companies’ websites.
Body imaging CT scans use special X-ray equipment to gather image data from different angles around the body. Digital processing of this information produces cross-sectional images of body tissues and organs in either two or three-dimensions.
MRI scans are non-invasive and work by detecting the body’s response to strong magnetic fields. Similarly to CT scans, computers are then used to construct visual images from the information gathered by the scan.
Are these health checks reliable?
The Nuffield Council mentions several examples of journalists and academics investigating the information provided by DNA profiling companies. In one newspaper article, a journalist compared the test results of several companies including GeneticHealth (a UK firm), deCODEme (based in Iceland) and 23andMe (an American organisation). There was considerable variation in the way in which information was provided and specific risk predictions also differed considerably. For example, when a healthy man had his risk assessed using these gene profile tests his risk of developing exfoliation glaucoma was predicted at 91% below average by one company, while another estimated the risk at 3.6 times more likely than average.
In a scientific review of the evidence behind these profiles, researchers tested at least 69 different SNPs in 56 genes. There were 260 meta-analyses for 32 of these genes, which examined 160 unique disease associations, of which only 60 (38%) were found to be statistically significant. Among these 60 significant associations, the strength of the link was generally modest, (odds ratios ranging from 0.54 to 0.88 for protective variants and from 1.04 to 3.2 for risk variants).
How can these services be a problem?
Genetic profiling is a relatively new technology and the link between particular genetic sequences and certain diseases is still unclear. Research, usually single trials, regularly reveal new potential links in high-risk groups. The results are sometimes not confirmed in further studies. A further problem is that companies can apply the tests to healthy people who may not have had any symptoms and for whom the test was not intended. This means that many of the tests do not accurately predict diseases and that many patients can be offered false reassurance or may be unnecessarily alarmed by the outcome of the tests.
The commercial genetic tests that sequence large amounts of the genetic code are often looking for variations linked to common diseases. There is considerable variation in the findings from the same sample tested by different companies and a scientific review concluded that the increased disease risk associated with the genes that the companies tested for had either not been sufficiently investigated or were “minimal to not significant” says the council.
Scans that use Magnetic Resonance Imaging (MRI) also often suggest health conditions that are not causing a problem and might never do so. In particular, the identification of benign abnormalities can lead to further unnecessary investigations. CT scans, which use X-rays, can pose a radiation risk.
MRI scans are particularly sensitive at anatomical detail and can lead to a high detection rate of things that later on turn out to be normal (false positives). In addition, some diseases are difficult to identify using MRI and in such cases, a patient may wrongly believe they have been given the ‘all-clear’ (false negatives). The NHS controls the use of imaging for NHS patients but currently there is no specific regulation that applies to private providers of body imaging in the UK.
Are there recommended ways to have these checks?
Within the NHS, DNA tests for single gene disorders and those disorders with a strong inherited basis are made available in a directory after evaluation by the UK Genetic Testing Network (UKGTN). In 2007, the directory contained molecular genetic tests for 359 diseases. The network aims to ensure the provision of high quality genetic testing services for all NHS patients in the UK by making recommendations to commissioners on new NHS services.
The PHG Foundation (Foundation for Genomics and Population Health) and the Royal College of Pathologists both recently called for regulation of direct-to-consumer DNA profiling. Others say that the UKGTN should also regulate DNA profiling offered by private firms.
Some people referred to in the Nuffield Council report maintain that the current regulatory system is satisfactory and that individuals cannot usually be harmed by the knowledge provided by multi-factorial DNA profiles.
Where should I go if I want reliable information?
The National Genetics Education and Development website was set up to inform and provide genetics education.
The PHG Foundation is an independent not-for-profit public health organisation. It focuses on the translation of science and biomedical innovation to improve health, especially genome-based science and technologies and the actions needed to change healthcare policies and services to deliver the benefits of research to populations worldwide. http://www.phgfoundation.org/
SNPedia is a website that shares information about the effects of variations in DNA. It references peer-reviewed scientific publications. http://www.snpedia.com/index.php/SNPedia