Author: Kayla Otoo
Editors: Emily Yu, Ethan Tai
Artist: Becky Li
Around the scientific community, there has been chatter about the slow pace at which genomics is being applied to clinical medicine due to the many changes in training necessary. First and foremost, the human genome consists of approximately 20,000 genes and over 3,000,000 proteins. Humans primarily have the same genes; there’s less than a 1% variation. This variation in DNA amounts to an individual's genetic makeup, which can alter how they respond to certain medications. Just over a few decades ago, the Human Genome Project was launched. Thousands of researchers across various continents—which came to be known as the International Human Genome Sequencing Consortium— gathered to create this project in pursuit of generating the first sequence of the genome. Since then, we have seen many advances within the healthcare industry, including new fields of medicine such as pharmacogenomics.
Pharmacogenomics is the study of how an individual's genetic makeup can influence their response to a certain medication. It falls under the field of precision medicine, which refers to personalized treatments based on genes, environmental factors, and lifestyle. The study of pharmacogenomics is carried out through genetic testing. It is widely ranged, as they can look at one or several genes that have an impact on the breakdown of medication. A pharmacogenomic test consists of a blood sample or buccal (cheek) swab. The sample is then sent to a lab where a technician reviews changes to identify specific changes in DNA. There are many situations in which one person may need pharmacogenomics testing, such as if the person has high cholesterol, depression, cancer, platelet disorder such as thrombocythemia, HIV, and immune system issues. Moreover, pharmacogenomics can be applied to many different areas of healthcare, such as the cardiovascular system. In 2003, two reviews of pharmacogenetics were published in The New England Journal of Medicine. One review dove into the many preventative drugs for cardiovascular disease, such as warfarin and clopidogrel, which have narrow therapeutic indexes. Therefore, small differences in blood concentration may indicate drug toxicity. Warfarin is an oral anticoagulant, meaning its function is to prevent/treat blood clots in blood vessels as well as the heart. Oftentimes, it is responsible for emergency visits. In 2004, studies of Warafin changed immensely with the discovery of vitamin K epoxide reductase complex subunit 1 (VKORC1), and single-nucleotide polymorphisms (SNPs) in VKORC1 having an impact on the target international normalized ratio (INR). Later in 2009, 1000 Swedish patients who were taking Warafin were studied in a genomewide association study. The results of the study showed that there were two major signals: CYP2C9 and VKORC1. When the author removed this signal, they observed an additional signal, hinting another cytochrome P450 gene: CYP4F2 was involved. The variant CYP4F2 was a catalysis for vitamin K oxidation thus a carrier would require an increase in the warfarin dose. Both genotypes VKORC1 and CYP2C9 were responsible for 30-40% of the total variation in the dose. These results prove the correlation between a person’s genetic makeup and response to certain drugs. In addition, the Journal explored various pharmacogenomic examples. These include the treatment plan for patients with hepatitis C virus (HCV) and the discovery that, in cancer pharmacogenomics, looking at the variation of a patient tumor genome and germline genome can serve as a guide for their response to antineoplastic therapy:cancer treatment.
Even though pharmacogenomics has many benefits in medicine, it does bring potential limitations. Although an individual’s genetic makeup can help in prescribing treatments, it fails to fully describe how a body may process medication. Thus, many factors must be considered, such as other medications a person takes, current health conditions, and lifestyle choices. However, the potential benefits outweigh the limitations. With pharmacogenomics, the healthcare system is safer, as doctors can prescribe medications that may prevent adverse reactions from occurring. Similarly, the Food and Drug Administration (FDA) has added warnings to drug labels about pharmacogenomic variations that may affect drug response. Healthcare costs have plummeted due to efficient prescriptions ,which 64% of studies have proven cost-effective, and researchers can discover new medications that target specific gene changes. Globally, more studies in pharmacogenomics are being conducted which hopefully will result in a safer, healthier, and more efficient world.
Citations:
Cleveland Clinic. “Pharmacogenomics.” Cleveland Clinic, 4 Oct. 2023,
Dere, Willard H. , and Tamas S. Suto. “The Role of Pharmacogenetics and
Pharmacogenomics in Improving Translational Medicine.” Clinical Cases in Mineral
and Bone Metabolism, vol. 6, no. 1, 2009, pp. 13–16,
Liewei Wang, Liewei, et al. “Genomic Medicine: Genomics and Drug Response.” The New
England Journal of Medicine , New England Journal.
National Human Genome Research Institute. “Human Genome Project.” National Human
Genome Research Institute, 24 Aug. 2022, www.genome.gov/about-
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