HUMAN beings are like snowflakes: every single one of us is completely unique, and yet 99.9 per cent the same. The human genome is like an instruction manual for life. All of us have it, and for the most part the manual is identical, except for the occasional inconsistency, like a typo here and there.

Deviations in our genome can have no effect whatsoever, or they can dramatically impact our health. These tiny differences can dictate what diseases we may be predisposed to, and how we respond to particular medicines and therapies.

As we learn more about the relationship between our biological characteristics and disease, we’re becoming better at preventing and treating illness. This burgeoning medical approach is known as ‘personalised medicine’, and advocates the treatment of patients based on their unique cellular, genetic and molecular make-up.

A key aspect of personalised medicine is focused on using genetic clues to help doctors identify individuals’ vulnerability to certain diseases. Small anomalies in our genes can leave us at greater risk of all sorts of diseases, from cancers to Alzheimer’s.

But thanks to technological advances and the hard work of scientists, we now know the relationship between certain genes and associated disorders.

Once we identify the genetic culprit for an affliction, we need to be able to test people to see if they have it. Scientists in Oxfordshire are part of a global movement to seek out more information on the biological triggers behind illness and ways of screening people for these triggers.

Because if we can develop the means to identify and screen for a greater number of gene-related diseases then it becomes easier to pre-emptively assess and protect the vulnerable.

For instance, the actress Angelina Jolie underwent a double mastectomy last year after discovering she carried the BRCA1 gene, which put her at an 87 per cent chance of developing breast cancer. Thanks to our knowledge of the gene’s link with cancer and our ability to screen for the defect, doctors were able to perform a preventative operation that could quite literally have saved Jolie’s life.

But personalised medicine is not just useful for prevention, it can also help to inform treatment options when a person becomes unwell.

Most of the medications we currently take are designed to work for the majority of people. But because of minute biological differences, we respond differently to medication. That’s why drugs come with a long list of side-effects – there’s variation in the way that different people react.

But when it comes to serious medical issues, like cancer treatment, it’s vital that we choose the best therapy for the individual. Some people respond well to chemotherapy, others don’t. But how do we know before we put somebody through treatment what will be best for them?

By scrutinising genetic and molecular clues, we’re becoming better at dividing patients into different groups based on their individual biological characteristics. We can then tailor treatments to a specific group.

A drug that hasn’t worked for the majority of people may work wonders on one specific group. But to know that, we first need to know how certain biological characteristics relate to individuals’ responses to treatment.

There’s much work to do in this field, and early stage research will be vital in making those links.

Our world-leading local science supports a variety of research into personalised medicine, and as we learn more about the genetic, cellular and molecular basis for disease, we’re becoming better equipped to assess and treat the individual.

No two people are exactly alike, and so advanced medicine is increasingly reflecting the fact that, on the deepest biological level, we are all snowflakes

* Mary Cruse is the science communicator at Diamond Light Source, the UK’s national synchrotron science facility at Harwell Science and Innovation Campus.