Pharmacogenetics
One of the newest and most promising fields to emerge in genomics, pharmacogenetics explores how genetic variation within individuals can cause different responses to specific drugs.
Variations in drug response can be attributed to a variety of causes—diet, environment, even general health just to name a few. In the past, research into the effect of an individual’s genes on drug response has been limited by factors such as high cost of genome sequencing and the slow speed of any sequencing process. However, new emerging technology has significantly decreased both of these limitations. Furthermore, a 1998 study in adverse drug reactions among hospitalized patients found that in 1994 over 2 million experienced some adverse drug reaction and over 100,000 died due to an adverse drug reaction.1 A 2005 study showed the costs of such adverse drug reactions were almost equal to cost of the drug treatment in the United States.2 New pharmacogenetic research seeks to solve these problems by deciphering how genetics can change how metabolic pathways recognize and utilize a common drug.
Pharmacogenetics first began in the 1950s when doctors observed that a small percentage of Caucasian patients reacted much slower to the effects of suxamethonium chloride, a muscle relaxant. Years of study led scientists to discover that 1 in 3500 Caucasian patients have a variation in a gene called N-acetyltransferase. The N-acetyltransferase gene makes an enzyme which greatly affects how fast certain families of drugs are metabolized. With patients who had a “slow” variation of the gene, suxamethonium chloride is metabolized much more slowly. Thus, these patients require high doses for the muscle relaxing effects to take effect. Suxamethonium chloride is just one of many drugs which are now being flagged as having drastically different effects on an individual due to their genetics.3
Now, doctors around the world have begun to apply principles of pharmacogenetics to their own practices. Pharmacogenetics has begun to allow doctors to personalize treatments and dosages for medicine based on the patient’s genes with an algorithm and eliminate the months of clinical trials needed to determine the dosages. As new practices and research unveils, some criticisms have been raised of pharmacogenetics. Some critics of pharmacogenetics argue that there is no way to allocate resources such that the drugs which arise from pharmacogenetic research would be too costly since only a limited number of people can take the altered variations. Furthermore, some believe the potential for financial gain by a biotech industry creating such drugs would outweigh their interest in achieving valid research and protecting subject health. Still, the majority of both doctors and researchers appear to support this novel field and see its potential as helping more people than it will hurt. The information of drug effect to certain enzymes is publicly available on PharmGKB.
As the field of pharmacogenetics grows, personalized medicine becomes more and more a reality. Utilizing one’s genes and how they work in terms of drugs and treatment is quickly transforming the healthcare industry.