Do You Really Want To Know What Your Genetic Code Says About You?

by jeeg 18. December 2013 21:46

It took 12 years and $3bn to sequence the human genome and figure out the code in our DNA. These days, people can post off a blood sample and get information on their genetic inheritance for as little as a couple of thousand dollars. This drastic reduction in cost, time and effort is fuelling new hopes for what humanity could do with enough data on DNA – data that is now being sought in projects from the recently announced Saudi Human Genome Programme (SHGP) to the UK’s 100K Genome Project. But asking people for their DNA and giving them the limited information that can be derived from their genomes is an ethical minefield, throwing up privacy issues and the right not to know, as well as the potential societal impact of freely available genetic data.

Saudi Arabia’s genome project, run by the King Abdulaziz City for Science and Technology Partners with the help of Life Technologies, was announced last week. It aims to analyse 100,000 genomes to identify the causes of disease in the Saudi population and the Arab world. The ambition is to have a Saudi-specific database that will help to provide personalised healthcare in the Kingdom and identify genetic diseases affecting Arab people. Brian Meyer, chairman of the department of genetics research centre at the King Faisal Specialist Hospital and Research Centre, who is working with the project, told Forbes that rare familial disorders were relatively frequent in Saudi Arabia.

“This project will identify causative variants for these disorders which will form the basis of diagnostic tests, carrier screening and disease prevention,” he said.

“The SHGP will also identify variants associated with common disorders including diabetes, cardiovascular and neurological diseases. The cataloging and validation of these variants will position Saudi Arabia and the Arab world to enable the adoption and practice of personalised medicine.”

With rare genetic disorders at issue, the benefits to gene sequencing are clear. Knowing about predispositions to genetic disorders that are treatable or preventable could help to save lives. But genome testing doesn’t always produce a clear result. Would knowing that you could one day get cancer have adverse psychological effects, particularly if there was nothing you could do about it? Even if there is something that can be done, how strong does the probability have to be for someone to take drastic action?

The problems were amply illustrated by the debate around actress and celebrity Angelina Jolie’s choice to have a double mastectomy after discovering she had a high risk of breast cancer. Despite the fact that her chances of contracting the disease were quite high at 85 per cent, her decision was criticised as well as lauded.

The value of knowing what your genes might tell you is a subjective one, according to Dr. Peter Mills, assistant director of the Nuffield Council on Bioethics in Britain.

“It depends very much on those involved and on their assessment of the implications for them and their family,” he said. “Even if there are no interventions available, people may want to know in order to plan their lives in the light of the information.

“But individuals will respond differently. For example, told that they have an increased risk of genetic disease, some may respond fatalistically, while others may make major lifestyle changes to try to mitigate the risk. There’s certainly a risk of fixating on genetic factors and overstating their significance, particularly in a context where interpretations are evolving as knowledge advances,” he warned.

Being part of government-sanctioned and well-funded projects like the SHGP and Britain’s 100K programme means that subjects will have access to doctors to help them assess their results, which will have been found using well-supported methodologies. The same may not be true of the consumer tests that are out there, allowing people to send off a blood sample for a quick result.

“For most people, genetic sequence data will be hard to make sense of without the help of an expert. We previously considered this issue in relation to direct-to-consumer genetic tests and one of the things we recommended was that doctors should receive specific training on advising patients about direct-to-consumer genetic profiling and about making referral decisions on the basis of these tests,” Mills said. “We also concluded that the companies that provide these tests should provide clearer information about the limitations of the results to potential customers.”

George Church, professor of genetics at Harvard Medical School and director of America’s open-access Personal Genome Project, pointed out that people needed to know what they were getting when they applied for DNA testing. Whole genome sequencing determines the complete DNA sequence of a sample, but other lab processes examine smaller parts of the genes. Some tests analyse single-nucleotide polymorphism (SNP), looking at DNA sequence variations, while exome sequencing examines the part of the genome formed by a type of nucleotide sequence known as an exon.

In each case, the tests are looking for markers in the sequence, which could take the form of abnormalities like translocations and inversions. A translocation is a chromosome abnormality caused by the rearrangement of parts between chromosomes. This kind of abnormality is common in cancer, where the translocation joins two otherwise separated genes. An inversion is another kind of rearrangement in which a segment of chromosome is reversed end to end. Inversions are frequently harmless, but the most common one seen in humans, on chromosome 9, is suspected of being linked to increased risk of miscarriage or infertility for some people.

“Whole genome sequencing is much more accurate than SNPS or exomes for detecting translocations and inversions, which can be very impactful,” Church said.

Even if people avoid finding out for themselves what their genes might have in store, any family member who decides to get their DNA looked at could inadvertently reveal markers that could affect the whole family.

“In some cases the information (or a strong indication) might come about as a result of someone else’s test. So access to or refusal of genetic information also implicates others. We require a carefully nuanced understanding of privacy to understand how to respond to this,” Mills said.

Privacy has been a large part of the discussion around the UK’s 100K Genome Project. Britain’s programme is also looking for 100,000 genetic sequences, but it hopes to share the information with researchers on an open access basis. Although volunteers’ names and addresses won’t appear on the record, the project is aware that they’ll be identifiable and is warning participants that their privacy can’t be guaranteed. The project is similar to those already going on in the US, Canada and Korea.

There are a number of fears about the idea that genetic information could become freely available, from the obvious concerns about effects on insurance premiums and employment all the way to more science-fiction-inspired worries that society could become divided along genetic lines. ‘Designer babies’ – made to order from a genetic menu – and a society dominated by a genetic elite are some of the more exotic fears about DNA research.

Mills pointed out that there are some cases when there might be good reasons for an employer to know about genetic markers, for example, being aware that a fighter pilot is at risk of blacking out at high altitude. But any discrimination based on DNA data is already being legislated for. The Genetic Information Non-discrimination Act (GINA) of 2008 covers both health insurance and employment in the US, while in Britain, insurers don’t discriminate by agreement under the Concordat and Moratorium on Genetics and Insurance.

Even with regulation in place, fears remain. After all, discrimination based on race and gender is also illegal, but no-one would argue that that’s managed to put a complete stop to it. While it’s relatively simple to tackle overt discrimination, it’s a lot harder to change how people think.

Harvard’s Professor Church said that scientists and the media would need to work together to educate the public about genetics, just as they had done on other controversial topics like GPS and mobile phones. The Saudi project’s Meyer also laid the responsibility on scientists to educate the public, but said that communities would also need to “build standards to benefit from genetic data without prejudice”.

Mills also explained that it might be harder to discriminate based on genetics than people think. Although the Saudi project is hoping to help identify markers that exist in Arab people, DNA research is unlikely to reinforce existing racial discrimination.

“To think of genes in terms of ‘race’ is what philosophers call a ‘category mistake’: the concept of ‘race’ is not inherent in the genome.

“There is a danger of overstating the role of genes, and it’s important to recognise that every one of us has a mixture of common and mutated variants. There is no ‘normal’ at the genome level but this does not sit comfortably with hype surrounding genetic testing,” he said.

“Scientists need to help spread a measured and proportionate understanding of the role that genes play in relation to other physical and environmental conditions.”

While organisations like the Nuffield Council on Bioethics run consultations on the ethical issues raised by uses of genetic and biomedical data, the science gallops ahead, as it must do if humanity is to realise the promise of genome sequencing. People’s high hopes of the original 12-year Human Genome Project have not yet been fulfilled, because being able to read the code is not enough. Much more data from as many subjects as possible is necessary to start reaping the greater benefits – targeted healthcare that could prevent some diseases and eradicate others and personalised, precise medication that could save and extend lives.

“What is certain,” said Mills, “is that we will never discover the benefits if we don’t do the research.”

Brid-Aine Parnell, Forbes

 

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