Genetic technologies and human health

Questions like this once seemed confined to the pages of science fiction. But they have now become a realistic possibility, thanks to rapid developments in genetic technologies over the past 70 years.

Since the discovery of the structure of DNA in the 1950s, geneticists have made new discoveries at a breathtaking rate. In 1982, the first drug (insulin to treat diabetes) was produced using genetic engineering, followed by the first trials of gene therapy in humans in 1990.

At the same time, sequencing a human genome has become simpler than ever. The original Human Genome Project took 13 years and cost $3 billion. Today the same process takes three days and costs less than $1,000.

But before we go any further, let’s see what you already know about genetics.

Rapid scientific developments are not uncommon. Less than 70 years after the Wright brothers completed the first successful powered flight, three NASA astronauts flew to the Moon - 385,000 kilometres away.

However, the speed of recent developments in genetic science has thrown up a range of economic, environmental and ethical issues that society is still attempting to process. The fact that your genome can now be sequenced safely and relatively quickly and cheaply means that the difficulty of carrying out related genetic procedures - for example genetic testing or genome editing - is also reduced. It also opens up the technology to a far wider range of individuals and organisations.

So how do you feel about this? How do you think using these technologies might change society? Here we will explore some of the key genetic technologies and probe some of the dilemmas and debates around their use.

These are some of the ways in which genetic testing is used in the UK:

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  Patients provide a blood sample, which can be analysed for a gene or genes linked to a specific disorder or that person's entire genetic code.

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  This is usually processed in a laboratory, although tests for individual genes that can be done on the spot are emerging.

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  Usually just a few genes are tested, but there are whole-genome approaches that look at every letter in your DNA. These include the 100,000 Genomes Project, which is focussing on cancer and rare diseases.

For some people, this level of genetic intervention raises concerns. What if there are unforeseen side effects? What if the technology gets into the wrong hands?

Let’s take a look at the story of a British baby called Layla to put some of these questions into a real-life context.

Leukaemia is the most common cancer in children under the age of five. In the UK over 85% of affected children survive for five years or more after their cancer is diagnosed. However in 2015, doctors at Great Ormond Street Hospital, London were treating a baby called Layla Richards, whose leukaemia had not responded to any of the conventional treatments.

Knowing that Layla would die without treatment, they turned to an emerging technique which involves extracting a patient’s own T-cells (an immune cell that targets cancers) and genome editing them to make them more effective at targeting leukaemia. These T-cells are then returned into the patient’s body.

Layla Richards did not have enough of her own T-cells, so doctors used T-cells from a donor. This meant that as well as using genome editing to attack the cancer, doctors also carried out further editing to ensure that the donor T-cells wouldn’t be rejected by Layla’s immune system. So there were two levels of genome editing - an unprecedented and pioneering achievement.

The treatment worked. Two years on, Layla Richards is healthy and her cancer hasn’t returned. Layla’s treatment involved somatic cells – which means that the genetic changes in her DNA won’t be inherited by her children. She will continue to be monitored to check for any complications. If further trials of this procedure are successful, then the treatment could become more widely available in the future.

But it’s not just the genomes of children and adults that can be edited using this technology. It is also possible to edit the genomes of embryos.

Because this editing is done at the embryonic level, it means that the change would be permanent, and may be inherited, a process known as germline editing.

It is currently illegal in the UK and US to implant a genetically altered embryo into a woman’s womb, which means that this technique could not be used unless the law is changed. Scientists have said much better evidence on whether the treatment is safe and effective, as well as inclusive public debate, is required before any change in the law should be considered.

Those in favour of using genome editing to treat genetic diseases in embryos argue that it diminishes suffering, and could reduce costs to the wider health system. Those opposed believe that it will reduce respect for difference and increase pressure on groups with characteristics that are labelled as a ‘disorder’.

Do you believe that genome editing should be used in the clinic to treat embryos likely to develop genetic disease, rather than just for research? For some, it is unacceptable because there are alternative options for parents who do not wish to pass an inherited genetic condition down to their children. In this argument, genome editing should only be used as a last resort.

These alternative options are:

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  Parents can choose to adopt. Or they can use a donated embryo that has no direct genetic connection to themselves.

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  Following IVF, it is possible to screen embryos for an abnormal version of a gene and only implant those that will not develop a genetic disease in the woman's womb.

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  Some genetic diseases can be managed. For example, in the case of cardiomyopathy, patients can be monitored, can avoid overexertion and can take medication to regulate their heart rate.