Genomic medicine and the future of personalised medicine

A relatively new branch of medicine is emerging called genomic medicine.  This involves whole genome sequencing to help to diagnose diseases.  In the next decade or so, this kind of treatment could be routine, with hospitals using a patient’s genetic fingerprint to determine whether their disease has a genetic basis.  In the more distant future people may have their genomes sequenced as part of screening procedures or even to determine their health insurance premiums.

In June 2013, the American college of Medical Genetics and Genomics published a set of guidelines stating that if a genome sequence shows a defect in one of 56 genes, the patient should be informed.  These guidelines beg the question of whether routine disclosure of genetic disease would always be welcome: for example would parents want to know what their child might die of in later life?  Would genomic medicine make parents more worried about their children’s potential diseases?

Currently most people are curious enough to want to know as much as possible on their own genome, but because sequencing looks at genes, what do certain results say about siblings or other members of the family?  One person’s decision to have their genome sequenced can have serious effects on the lives of their relatives.  This sort of problem has become so significant that specialised ‘genetic counsellors’ can now advise and help families to deal with the consequences of genetic sequencing.

The cheaper and less complex method for finding mutations is to sequence the exome, the regions of the genome which code for proteins.  Although this is less complex and produces less data than using Sanger sequencing, most people will still have a huge number of mutations and differences compared to the reference human genome.  Exome sequencing only measures 1% of the whole genome, yet most people will find they still have tens of thousands if not hundreds of thousands of mutations.  Most of these will be harmless because of the redundancies of our metabolic pathways.  However, we know that certain mutations will increase your chance of getting Alzheimer’s disease, for example 20% of Europeans have a single mutation on chromosome 19 which approximately doubles the chance of getting Alzheimer’s disease.

As this technology continues to develop, we will be able to predict more accurately the chances of getting specific diseases and which drugs will work best to prevent them. Computers will be able to pick out mutations and doctors may be able to use them to explain certain symptoms.  Genomics will become more and more important as geneticists develop new methods to find the ‘important’ mutations.  Genomic medicine will also significantly change the pharmaceutical industry with a move away from generic medication towards new drugs which target specific problems in a new market of personalised medicine.

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