by Annie Derry
The idea of tailoring treatment to best fit a patient’s needs has been around for as long as medicine itself. Each individual is different, and bedside manner is, of course, tailored according to a patient’s personal circumstances. Medicinally, we can currently alter treatment to try and ensure that medications are right for a patient, considering their medical history and potential side effects.
As we have come to know more about pharmacology, disease, and their links to the genome, more specific and even individualistic medical treatment has become more of a real possibility. The idea of personalising medicine is to move away from the blanket approach currently used for a lot of disease treatments, and to delve further into the details about each patient’s genetic make-up in order to see their risk of developing certain diseases and what their potential responses to therapeutic methods may be. Studying a patient’s unique genome could prove vital in providing the best possible treatment, in the safest way, as well as giving the potential for earlier diagnosis and risk assessment. It promises to, overall, improve healthcare for patients while keeping costs relatively low.
What changes how we respond to drugs?
Many factors affect how we respond to anything that we consume or put in to our body. Our physical properties such as, height, weight, age and gender can all affect how we assimilate and metabolise drugs. These fundamentals are already considered in pharmacokinetics and pharmacodynamics when calculating dosage. It is now understood that there are also certain proteins that can affect drug metabolism, and scientists can now up to a point, predict, how a patient might respond to a drug based on the expression of these proteins from their genes. There are now technologies known as HTS (high throughput sequencing) techniques available that allow millions of DNA fragments to be sequenced simultaneously. The rise in genomic technology has seen the length of time taken to sequence a whole genome decrease from 13 years (the first ever human genome sequenced) to a matter of 1 or 2 days. Most of the time it is only the exome (expressed part of the genome – the exons) that are sequenced for medical purposes, due to time and cost restrictions. However, sequencing whole genomes also allows scientists to develop an understanding of the unexpressed, or ‘nonsense’ DNA regions.
How is personalised medicine currently used?
All over the world preventative measures can be taken by those who wish to have their genome privately sequenced and analysed, for around £1000. This involves a whole exome sequencing and includes estimations of your genetic disposition towards various diseases such as cancer and some rare genetic forms of Alzheimer’s disease amongst others; although, most diseases are still heavily impacted by environmental factors. In the NHS, similar genetic analysis is now commonplace. In her 2017 annual report the Chief Medical Officer for England, Dame Sally Davies, stressed her excitement for the genomic revolution and her ambitions for genetic testing to be as routine as blood testing patients in the next 5 years. This already occurs for those who are deemed at higher risk of having a genetic disposition for a disease, e.g. testing people for variants within the BRCA1 and BRCA2 genes to determine any higher risk of breast/ovarian cancer. This allows people to assess their risk and take any precautions necessary to prevent the cancer/to reduce its effect in their life.
Potential problems?
The benefits of personalised medicine seem varied and undeniable. However, there are some cases where genome analysis could be taken out of context and used in the wrong way. An extreme example of the potential capabilities of genomic analysis is that of the Chongqing Children’s Palace, a summer school in China, which provides a genome sequencing service for parents who want to know their child’s ‘capabilities’. It is claimed that they can use the children’s genome sequence to determine their best qualities, including what jobs they would be best at, and what activities they should be participating in. The ethical issues with this speak for themselves, and without taking the results with a pinch of salt and an understanding that these factors cannot be accurately determined just by genome analysis, there is potential for a big problem.
In the U.K. there are also some concerns about the use of patient data, and whether information gathered about patients from genetic testing could get in to the hands of organisations other than the NHS. There are worries that this could result in changes to people’s ability to get life insurance, mortgages and other forms of loans. It is reasonable to assume that for people deemed at high risk of developing life-threatening disease, these things could be heavily affected if their genome data is not protected.
Overall, the pathway we are on to a more personalised medical experience is an exciting and quickly moving one. It is important to remember: we are fundamentally defined by our genetic make-up, but most diseases are also profoundly impacted by our surrounding environment. We cannot currently wholly and accurately define all disease risk using genome analysis, but it can certainly help our understanding of personalised medical treatment for each unique patient. Genetic testing and sequencing will almost certainly become a routine part of our lives, hopefully for the better!
Want to learn more? This blog post was based on:
Lone Frank – My Beautiful Genome Personalised Medicine
Personalised medicine in the UK
Sequencing your genome, what does it mean?