07 January 2010
ByAppeared in BioNews 540
The Progress Educational Trust (PET) dedicated its annual conference Does Genetics Matter? Help, Hype and the New Horizon of Epigenetics to answering these questions. The final session, entitled 'So Are We Making Progress?' looked broadly at the future of genetics - its impact on 'the man on the Clapham Omnibus' and on scientific progress.
The session was boldly chaired by Professor John Burn, Head of the Institute of Human Genetics at Newcastle University, and panellists from the previous sessions participated. Towards the end, Professor Burn described how, when young, his son had planted a conker and told him he wanted to grow a tree so he could build a tree house. He offered this story as being representative of what the session identified as among the leading challenges facing genetics today - managing expectations.
He started the session by asking everyone to estimate when genetics will revolutionise clinical medicine. Professor Mark McCarthy from the Oxford Centre for Diabetes, Endocrinology and Metabolism felt there is no 'magic' or 'watershed' moment when this will happen. The panel agreed.
Professor Steve Humphries, Director of the Centre for Cardiovascular Genetics at University College London, argued the timing would depend largely on how efficiently health systems approve and incorporate the genetic tests developed, touching upon another popular topic of this session - regulatory policy.
He gave two examples - testing for hypercholesterolaemia and a type of inherited breast cancer from a gene called BRAC1 - to show attitudes in the UK's NHS determine the speed that genetics impacts on clinical practice.
Hypercholesterolaemia is an inherited disorder that significantly raises the risk of heart disease in the over-50s. According to Professor Humphries, a genetic test to screen high-risk families already exists and the condition, once diagnosed, can be effectively treated with drugs called statins. Despite the potential for tests to save the NHS money by catching families before they develop heart disease, he says PCTs don't seem interested in funding them. Perhaps 85 per cent of the estimated 120,000 people in the UK genetically predisposed to this condition are unaware they have it.
Professor Humphries contrasted this with breast cancer treatment. Here, the NHS has quickly and successfully implemented genetic screening for women with a family history of breast cancer. They are screened for a known genetic mutation to the BRAC1 gene that causes an inherited breast cancer. If diagnosed early, this can be treated with Herceptin - dramatically increasing the patient's chance of survival.
Dr Christine Patch, Chair of the British Society for Human Genetics and a Consultant Genetic Counsellor and Manager at Guy's Hospital in London, warned hype is raising expectations about personalised medicine. Yet most research focuses on identifying traits and there may be no treatments developed for many years.
The panel seemed to agree that advances in genetics are frequently hyped in the media by exaggerating their predictive power and the proximity of future treatments. Professor Burn dared the panel to write headlines reporting genetic breakthroughs to the public. Most stumbled over their answers.
Professor McCarthy quipped that he would probably suggest 'common diseases are common'. This was presumably a play on the idea that common diseases have a number of causal genetic factors in 'common', but none can predict the disease in isolation. This is contrary to the claims of some private genomic screening companies and misleading news reports that newly-discovered risk factors are 'responsible' for the associated complex disease.
Despite monogenetic diseases being rare, the panel felt studying them helped deepen our understanding of the genetic causes of disease. Professor Humphries felt this was what he would say to journalists if there was a catchy way to express the concept.
A consumer journalist in the audience, meanwhile, suggested genetics in the media can help attract funding and support if couched in terms of costing lives and/or the NHS losing money needlessly by not making genetic tests available.
The discussion then moved onto the cutting-edge field of epigenetics. Sandy Starr, Communications Officer for PET and the Webmaster of BioNews, asked how valuable genome-wide association studies (GWAS) were because they had 'diminishing returns'.
GWAS map genetic variants associated with a particular disorder in unrelated populations. Since they are non-specific, they can generate questionable correlations, but they have also identified genetic variants with significant links to disorders. They have diminishing returns because, the more mutations identified, the lower the causal link with the disorder. No single mutation is sufficient or necessary to cause the disorder alone. Professor Karen Temple from the University of Southampton and Wessex Clinical Genetics Service, said, while GWAS research is valuable, she would prefer to understand the biology before treating the disease.
Audience member Dr David King, head of Human Genetics Alert, asked about the effect of epigenetics on evolution. Epigenetics refers to biochemical mechanisms that interact with DNA to selectively silence and activate gene expression in different tissues and at different points during an individual's development, lending an exciting new perspective to our understanding of genetics.
During a previous conference session, Professor Marcus Pembrey had discussed his research supporting epigenetic inheritance. He had found that epigenetic changes caused by a parent being malnourished or a smoker affected their children and grandchildren. In this session, Professor Pembrey discussed a 'soft inheritance' theory that epigenetics influences evolutionary trends. He said some research revealed small indications that epigenetics might drive early evolution, but evolution would later switch to genetics. This theory needs further investigation.
Discussion moved onto private companies offering online genomic scanning services directly to consumers (DTC). Sarah Norcross, Director of PET, said the UK Government's Human Genetics Commission has issued a set of common principles to regulate this industry. However, she wondered how it would operate and who should regulate it. She also wondered if the proposed principles will be too restrictive causing others to seek services abroad.
The panellists were not particularly convinced about the threat or popularity of this market and pointed to the recent insolvency of deCODE - a genetic testing company. One audience member asked whether, as these genetic tests become increasingly inexpensive, a divide would open. Testing companies would be divided into 'Ryanair' and 'British Airways' quality, with the 'Ryanair' budget option not providing genetic counselling. The panellists felt genetic counselling should be required, but were not concerned that DTC would undercut medical testing because people want to be tested by a physician when their health is at stake. All felt it is too early for these types of scans to have predictive value. Two audience members shared their experiences of participating in scans from 23andMe and deCODE - they found them to be generally non-descriptive.
The panellists felt the issue went beyond DTC testing to regulating genetic tests generally. It was suggested that perhaps the UK should have an independent regulatory committee like that for drug approval. Professor Burn supported uniform EU regulation, but was concerned that the EU would develop genetic policy when it does not yet recognise genetics as a medical specialism. The UK is more relaxed in its regulation of genetic testing, but the panellists demanded greater transparency and an end to corporations keeping data secret to protect intellectual property.
Dr Patch questioned why DNA and RNA testing should be regulated differently from other diagnostic testing. Audience member David Lyons disagreed, saying that DNA testing has a host of psychosocial consequences. Other panellists were more concerned about how these tests are practically implemented and finding funding for them, admitting there is no easy solution for the NHS, which relies on limited public funds.
Ultimately, it was clear from the discussion that whilst a metaphorical tree house was not going to appear overnight from the seeds of genetics research, meaningful research and our understanding of the causes of and treatments for human disease are advancing rapidly.
In the meantime, as Sarah Norcross said in her closing remarks, there are always headlines like 'Boffin Baffles Scientists for Future Gene' or 'Easy Genes: it's a SNP' to capture public support.