What is Pharmacogenomics?

Pharmacogenomics is the field of study about the effect of genes on an individual’s response to medications. It combines the science of drugs, pharmacology, with the study of genes, genomics, to establish effective ways to use medications in respect to the genetic makeup of each individual.

Conventional Medications

The majority of medications currently available on the market are targeted towards the general population, despite the fact that each patient may respond to the drug differently, according to their genetic makeup.

Some individuals may not experience a sufficient response to the standard dose, as a result of extensive metabolism of the drug. On the other hand, other individuals are more likely to experience adverse drug reactions, as their clearance of the drug is lower than normal.

Pharmacogenomics combines biochemistry are other pharmaceutical sciences with an enhanced understanding of DNA variations in the human genome to target these differences with pharmacological treatments.

The Human Genome Project

The Human Genome Project was a major publication that summarized the knowledge of pharmacogenomics and spiked interest in the field for future study and used in healthcare. Several findings were evident in this project, as follows.

Single nucleotide polymorphisms (SNPs) are the most common known genetic variation, with an estimated 11 million different variations in the human population. These alterations in the genome can often be used to predict an individual’s susceptibility to disease and response to a drug.

Structural variations of DNA can alter the structure of the chromosome and its overall function. This may be a change in the number of copies, inversion of the chromosome or translocation of genetic material.

The vast majority of the human genome (>99%) is identical in the entire population but approximately 0.5% is variable, and it is this that is targeted with pharmacogenomics.

Proposed Benefits of Pharmacogenomics

The ability to used targeted genetic therapies has the potential to improve medical treatment as we know it, increasing effectiveness and decreasing the risk of adverse effects. The benefits may include:

• Targeted therapies for specific diseases with optimal therapeutic effects
• Reduced damage to surrounding healthy cells
• Faster recovery time

The doses could be tailored to the individual’s genetic makeup and how their body processes the drug.  This is in contrast to conventional medication, which uses crude estimation techniques based on height and weight of the individual, which is then adjusted according to the response.

Challenges of Pharmacogenomics

Although it is evident that the potential utility of pharmacogenomics in healthcare applications is high, there are several challenges to be overcome before it will form a routine part of medical care.

For example, the response of most drugs is determined by several different genetic variants, which can make it difficult to predict the exact response of an individual. Additionally, other factors such as the environment and situation may influence the patient response to the medication.

Additionally, the integration of pharmacogenomics into healthcare services will require adjustments to the current system, including new ways to make decisions about choice of therapy.

The Future of Pharmacogenomics

Pharmacogenomics is still a relatively new field of study and its current use in practice is quite limited, particularly when its potential uses for the future are considered.

Extensive research is currently being undertaken in this area to allow the development of drugs that are tailored to specific individuals with unique genetic makeup. In particular, there is interest in genes encoding metabolic enzymes that alter a drug’s activity or an individual’s susceptibility to disease.

References

• http://ghr.nlm.nih.gov/handbook/genomicresearch/pharmacogenomics
• http://www.ama-assn.org/ama/pub/physician-resources/medical-science/genetics-molecular-medicine/current-topics/pharmacogenomics.page
• http://www.yourgenome.org/facts/what-is-pharmacogenomics
• http://www.geneticseducation.nhs.uk/downloads/0428PharmacistArticle08.pdf
• http://www.genome.gov/12011238

Further Reading

• All Pharmacogenomics Content
• Recent Advances in Personalized Medicine

Written by

Yolanda Smith

Yolanda graduated with a Bachelor of Pharmacy at the University of South Australia and has experience working in both Australia and Italy. She is passionate about how medicine, diet and lifestyle affect our health and enjoys helping people understand this. In her spare time she loves to explore the world and learn about new cultures and languages.