‘Dream’ of precision medicine getting closer

Book of you: The letters from just one human genome would fill a 61m high stack of paperbacks.

The UK’s chief medical officer has called on doctors to deliver her “genetics dream”: personalised medicine which is available for everyone. What does this mean? And is it a good idea?

Currently when you go to see a doctor, the process goes something like this: you present your symptoms. They draw on at least five years of training (probably more) to decide what is wrong with you. If they do not know, you are put through a series of tests in the hope that things will become clearer. (Sometimes they do not.) Eventually, the doctor will choose from thousands of different drugs or therapies or operations, hoping they will make you better. Often, finding the treatment involves a lot of trial and error.

What if this “diagnostic odyssey” could be revolutionised? That is the dream of Britain’s chief medical officer, Sally Davies, who yesterday outlined her vision for the NHS: personalised medicine that is available for everyone.

The idea of personalised medicine (sometimes called precision or genomic medicine) is not a science fiction fantasy. Over 31,000 patients have already had their genome sequenced by the NHS to help identify rare diseases. Doctors can also use the information to choose personalised cancer treatments with a higher chance of working, and a lower risk of side effects.

Now Davies wants the system to be no more unusual than an MRI scan.

A genome is a complete set of genetic material. In humans it is made up of around 20,000 genes, which in turn are made from 3.2 billion letters of DNA.

Around 99.8% of our genomes are identical to those of every other person on Earth. But the remaining 0.2% make each of us unique, determining our appearance, personality, athletic abilities — and our chance of getting certain diseases.

It took 13 years and up to $1 billion to sequence the first human genome. Now, it takes around $1,000 and a single day. The time and cost are expected to fall even further.

For now, personalised medicine is for people who already have diseases. But it is possible to imagine a world where it is available for everyone. This would not just mean treating illness better when it appeared, but trying to prevent it from starting.


Hold on, say some. That would mean everyone had their entire genetic makeup on file somewhere. That is a terrible idea; even if doctors kept it private, it might end up being hacked and falling into the wrong hands. It could be used by your employer or insurance company to discriminate against you. The only way to keep it private would be to avoid testing in the first place.

The risks are worth it, say others. Personalised medicine would not just be amazing for patients; it would be brilliant for doctors and hospitals, too. Time would no longer be wasted on failed tests and ineffective drugs. This would make healthcare cheaper, faster, and more effective than ever. Bring it on.

You Decide

  1. Would you want to find out the secrets of your own DNA?
  2. Should personalised medicine be available to everyone?


  1. Imagine that personalised medicine is now available everywhere. Write three “golden rules” to keep people’s genetic information safe.
  2. Draw and label a diagram showing human DNA.

Some People Say...

“Genetics do not always determine who we are.”

What do you think?

Q & A

What do we know?
Personalised medicine already exists for some diseases and cancers, but it is still in its early stages. Yesterday, Sally Davies said there were three million Britons living with rare diseases. She also said that in a recent study of cancer data around 60% of cancer patients had “actionable genes”, meaning they could benefit from personalised medicine.
What do we not know?
How quickly genomic science will advance, and whether it will be embraced by doctors and the general public. Patients might be wary of such personal data being stored by doctors, and doctors might take time to adapt to such a radically different approach to medicine. We also do not know just how far genomics should go — will it be limited to treating patients, or expanded to healthy people?

Word Watch

Currently in the UK personalised medicine is a “cottage industry”, says Davies, available in 25 labs around the country, with access depending on where you live or who your doctor is. Davies suggests centralising these labs so that all hospitals can make use of them.
Part of the UK 100,000 Genomes project, which aims to sequence 100,000 genomes from 70,000 patients and their family members in Britain. Once complete, it will take up 21 petabytes of data; the equivalent of 2,000 years of MP3 music. A petabyte is one thousand million million.
The four nucleotide bases of DNA are represented by four different letters: A, T, C and G. These are paired into rungs of a ladder, which is twisted into a double-helix structure. Your genome, found in almost every cell in your body, is the unique sequence of these letters that makes you who you are.
13 years
The Human Genome Project, led in the USA and completed between 1990 and 2003, involved hundreds of scientists from all over the world.
Companies raced to pass this milestone, first achieved by Illumina in 2014.


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