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06 Jan 2012 00:00
Doctors have drawn up plans to sequence the full genetic code of thousands of people in a landmark project to personalise their medical care. Volunteers will have all six billion letters of their genome read, stored and linked to their medical records to help doctors prescribe more effective drugs and other therapies.
The Mayo Clinic in the United States will launch the pilot study early this year as part of an ambitious move towards an era of “proactive genomics” that puts modern genetics at the centre of patient care.
The trial reflects a trend in medicine to use genetic information to identify patients who will benefit most from a drug and those who will respond better to an alternative.
The information locked up in the human genome can help doctors advise patients on lifestyle changes to stave off diseases they are at risk of developing but, in many cases, that advice is familiar and generic: focusing on healthy eating, exercise, drinking in moderation and not smoking.
But the Mayo Clinic trial goes further by giving doctors all the genetic information they need to choose the best drugs for a particular patient while minimising side effects. Many clinics already offer specific genetic tests to steer patient treatments but these are often used in a piecemeal fashion and reactively, for example, when a patient fails to respond to a drug or has an adverse reaction. Now the plan is for doctors to have a patient’s genetic make-up available to help to guide their prescriptions from the start.
Dr Gianrico Farrugia, the director of the Centre for Individualised Medicine at the Mayo Clinic in Minnesota, said the cost of sequencing a person’s whole genome—about 23 000 genes—had fallen so rapidly that it was now comparable with the price of a single gene test.
The project would help managers at the clinic to decide whether it made sense to read and store a patient’s whole genome early on, instead of ordering single genetic tests as the need arose. This shift towards whole-genome sequencing is expected to become more valuable as doctors and scientists piece together how multiple genes influence disease and how the body reacts to drugs.
“This is a trend that will definitely be found across the developed world in the coming two to five years,” said Tim Aitman, professor of clinical and molecular genetics at Imperial College London.
“The questions that arise are who is going to store the information, how is it stored securely, who has access and what are you going to do with information that you or the patient might not necessarily want to find out. There are some significant ethical and privacy issues and they are probably more difficult to solve than storing the information.”
Anneke Lucassen, professor of clinical genetics at Southampton University, England, said genetic testing was not yet good enough to give definitive information for patients. “Although the cost of a full genome sequence is getting to be very affordable, robust interpretation of what it means for an individual lags behind,” she said.
“There’s a lot of promise about tailoring treatments or modifying lifestyles, depending on particular genetic variation but, to date, with a few exceptions, the clinical utility of genome sequencing is limited.” —
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