“The genome generation”

On Monday night, I attended a public lecture organised by BrisScience entitled ‘The revolutionary impact of genomics on medicine & healthcare’ and I left feeling very inspired and optimistic (it’s nice to have a break from the monotony of cynicism sometimes). DNA sequencing technology has advanced rapidly in the last few decades, but I hadn’t realised that the implications for healthcare were so enormous and already in effect. In 2001, the cost of sequencing genomes was US$100 million and now it’s $1000. Just take a moment to let that sink in. Because the repercussions are HUGE.

The speaker was Professor John Mattick of the Garvan Institute of Medical Research in Sydney, and I found his enthusiasm pretty infectious. He described the intersection between nanotechnology and DNA sequencing as ‘beautiful’, a word scientists tend not to use lightly. Nanotechnology is something that I often just smile and nod unknowingly about, but the applications are astounding; we now have little devices that you can stick a sample in, plug into a computer and *SCIENCE WIZARDRY*, allow you to sequence DNA in real time.

So we’ve reached a point where it’s easy and cheap to sequence DNA – what does this mean for healthcare? Well, now we have projects like the International Cancer Genome Consortium (ICGC), the goal of which is to create a comprehensive catalogue of the genetic abnormalities found in 50 different tumour types. This will greatly facilitate research into the causes and treatment of cancer; Mattick described it as a new paradigm for cancer classification, based on molecular characteristics. Scientists have discovered many overlapping mutations between different cancers, which has led to readily available drugs being repurposed and providing positive treatment outcomes. Being able to sequence an individual’s genome doesn’t only have implications for treatment, but could also help uncover which cancers or genetic diseases a person is at risk of acquiring, which may allow for preventative measures to be taken.

This idea of personalised medicine, optimising treatments according to an individual’s unique set of genes, makes a lot of intuitive sense. It is easy to observe individual differences in drug responses; the example Mattick used was caffeine – some people are much more susceptible to the effects of caffeine than others, and this is due to variations in genes that code for liver enzymes. The liver is responsible for the metabolism of drugs; differences in enzyme genes can alter the function of the enzyme, increasing or decreasing its activity. These differences are also reflected between human populations; take alcohol metabolism, for example, which is primarily controlled by two enzymes – alcohol dehydrogenase and aldehyde dehydrogenase. Different versions of the enzyme genes are prevalent in different populations; East Asians, for example, predominantly have a gene variant which results in increased sensitivity to alcohol and lower levels of alcohol consumption and dependence.  

I’ve had direct experience with the ‘one-size-fits-all’ approach to drug therapy; I was prescribed lithium last year, the go-to drug for bipolar disorder, and I found it didn’t help me at all. Pharmacogenomics is a field which looks at how variations in drug response are multifactorial – influenced by a number of genes and environmental factors. This has enormous potential for the treatment of psychiatric disorders, especially those that are treatment-resistant. Finding effective treatments can be a long, arduous process of trial-and-error. Mattick envisaged that in the next five to ten years, an individual’s genome sequence will become a routine component of their medical records, which could mean significantly greater drug efficacy and safety. This is the ‘genome generation’ he proclaimed.

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