Dr Swarkar Sharma and Dr Ekta Rai
Pharmacogenomics, the study of how an individual’s genetic makeup influences their response to medications, is transforming healthcare worldwide. This cutting-edge field combines pharmacology, the science of drugs, with genomics, the study of DNA and genes; and their functions. The biological information of transmission of characters from parents to offspring is encoded and controlled by fragments of DNA called Genes. There are approximately 20,000-25,000 Genes in humans. These individually or in combinations, including interactions with environment, take care of composition and all the functions of Human body. During course of inheritance, from one generation to another, many a time some changes arise in DNA, which are called mutation or variations and are inherited to the next generation. These variations may affect functioning of a Gene. The variations, in the genes which are involved in processing of the medicines, may impact functioning of the medicines. By analysing variations in DNA of individuals, pharmacogenomics enables healthcare providers to predict how individuals will respond to certain medications, allowing for more precise, effective, and safer treatments. In this way, pharmacogenomics is guiding medicine into an era of personalized healthcare, where treatments are tailored to the unique genetic profiles of patients.
As diverse populations across the globe have different genetic variants, pharmacogenomics offers unique insights into how drugs behave in different individuals and ethnic groups. This article explores the impact of pharmacogenomics on healthcare with some examples from across the world, demonstrating how genetic variability influences drug response and the growing importance of personalized medicine.
Understanding
Pharmacogenomics
The principle behind pharmacogenomics is simple yet profound: genetic differences among individuals can significantly affect their response to drugs. These differences are often due to variations in specific genes responsible for metabolizing, transporting, and targeting drugs in the body. Such variations can influence whether a drug is metabolized quickly or slowly, its efficacy, or its likelihood of causing side effects.For example, some people may have genetic variants that cause them to metabolize certain drugs too quickly, rendering the medications less effective. Others may metabolize drugs too slowly, leading to an accumulation of the drug in their system and an increased risk of adverse reactions. Pharmacogenomics aims to identify these genetic factors and use that knowledge to optimize drug therapy for each individual.
Global Impact of Pharmacogenomics
Pharmacogenomics has the potential to significantly impact healthcare systems worldwide, particularly in regions with high levels of genetic diversity.
Africa, the bed of Human origin and home to genetically diverse populations, presents both challenges and opportunities for pharmacogenomics. The continent has a high burden of diseases such as HIV/AIDS, and pharmacogenomics is being explored as a way to improve the effectiveness of antiretroviral therapies (ART).One of the challenges in HIV treatment is the variability in response to drugs such as efavirenz, a commonly used antiretroviral. Variations in the CYP2B6 gene can affect the metabolism of efavirenz, leading to different responses among patients. Studies have shown that certain genetic variants are more common in African populations, making it crucial to consider these factors when prescribing ART. By incorporating pharmacogenomic testing into HIV treatment protocols, healthcare providers can better tailor therapy to individual patients, improving treatment outcomes and reducing the risk of drug resistance.
In the United States, pharmacogenomics is already playing a critical role in oncology, where genetic testing helps guide the treatment of cancer. The case of the drug trastuzumab (Herceptin) for breast cancer patients illustrates the power of pharmacogenomics. This drug is effective only for patients whose tumors overexpress the HER2 gene. Genetic testing allows doctors to identify which patients will benefit from the treatment, ensuring that the drug is used only when it is likely to be effective.Similarly, pharmacogenomic testing is being used to personalize chemotherapy regimens. For example, patients with specific variations in the DPYD gene may have difficulty metabolizing the chemotherapy drug fluorouracil, leading to severe side effects. By identifying such variations beforehand, doctors can adjust the dosage or select alternative treatments, improving patient safety and outcomes.
In Japan, pharmacogenomics is making strides in the treatment of mental health disorders. Medications used to treat conditions like depression and schizophrenia often have variable efficacy and side effects among patients. Genetic factors play a significant role in how individuals respond to these drugs.For instance, the enzyme CYP2C19 is involved in metabolizing selective serotonin reuptake inhibitors (SSRIs), a class of drugs commonly used to treat depression. Variations in the CYP2C19 gene can result in different levels of drug metabolism. In Japan, where certain variants of this gene are more prevalent, pharmacogenomic testing is being used to guide the choice and dosage of antidepressants, leading to more effective treatments with fewer side effects.
In regions with high genetic diversity, such as Jammu and Kashmir in India, pharmacogenomics has potential to shed light on how genetic variations influence the response to common medications. This region is home to diverse populations with distinct genetic backgrounds, and ongoing research is uncovering how these genetic differences affect the metabolism of various drugs.For instance, heart medications like beta-blockers may be effective in one ethnic subgroup but less effective or cause adverse effects in another. Variations in genes like CYP2D6 and CYP2C9, which are involved in drug metabolism, can lead to differing responses to these medications. Pharmacogenomics allows doctors to tailor treatments based on the genetic profiles of individual patients, improving outcomes and reducing the risk of side effects.
The potential of pharmacogenomics extends beyond the examples discussed above. As research continues to explore genetic differences in populations worldwide, personalized medicine will become an integral part of healthcare. By understanding how genetic differences influence drug response, healthcare providers can offer more personalized, effective, and safer treatments. Moreover, the integration of pharmacogenomics with other emerging technologies, such as artificial intelligence and big data analytics, promises to further enhance the precision of personalized medicine. By combining genetic information with other data points, such as a patient’s medical history and environmental factors, healthcare providers will be able to develop highly individualized treatment plans.Pharmacogenomics represents a paradigm shift in medicine, moving away from the traditional “one-size-fits-all” approach to treatment. As the field continues to evolve, pharmacogenomics will play an increasingly important role in global healthcare, improving patient outcomes and revolutionizing medical practice across the world.From the United States to Africa, and from Japan to Brazil, the impact of pharmacogenomics is being felt in diverse regions with different health challenges and genetic profiles. As more countries adopt pharmacogenomic testing, the dream of truly personalized medicine is becoming a reality, ushering in a new era of healthcare tailored to the genetic blueprint of each individual.
( Dr Swarkar Sharma is Associate Professor in Centre for Molecular Biology, Central University of Jammu and Dr Ekta Rai is Associate Professor in School of Life Sciences, Jawaharlal Nehru University, New Delhi.)
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