A review of literature on the pharmacogenomics of single-nucleotide polymorphisms

Abstract

Pharmacogenomics is the study of how our genetic structure determines the response to a therapeutic intervention. It is a rapidly growing field that aims to elaborate the genetic basis for differences in drug response between different individuals and to use such genetic information to predict the safety, toxicity, and/or efficacy of drugs in individual patients or groups of patients. Although drug–drug interactions and environmental factors significantly contribute to interindividual variability in drug response, genetic factors (e.g., inherited variability of drug targets, drug-metabolizing enzymes, and/or drug transporters) also appear to have a major impact on drug response and disposition. When a gene variant is associated with a particular drug response in a patient, there is the potential for making clinical decisions based on genetics by adjusting the dosage or choosing a different drug. Single-nucleotide polymorphisms (SNPs), also called SNPs, are the most common type of genetic variation among people. They are basically a substitution of a single nucleotide that occurs at a specific position in the genome. They occur normally throughout a person's DNA. They occur almost once in every 1000 nucleotides on average, which means there are roughly 4–5 million SNPs in a person's genome. Most SNPs have no effect on health or development. Some of them, however, have proven to be very important in the study of human health, especially in the field of pharmacogenomics. Researchers have found SNPs that may help predict an individual's response to certain drugs, susceptibility to environmental factors such as toxins, and risk of developing particular diseases. Scientists assess gene variants affecting an individual's drug response the same way they assess gene variants associated with diseases: by identifying genetic loci associated with known drug responses, and then testing individuals whose response is unknown. SNPs account for the most common genetic differences from person to person and pharmacogenomics explores how such changes in genetic makeup effect drug responses, resistance, etc., With our literature review, we aim to study some of the effects of these SNPs on drug responses in patients. The purpose of the study was to understand and implicate the effects of SNPs in modern medicine and how it can be applied to personalize health care for every patient. A systematic literature search was carried in search of studies pertaining to personalized medicine and implications of SNPs. A thorough search through PubMed, Google Scholar, and ProQuest revealed 61 relevant studies. All study types were considered eligible. Over the past 10 years, tremendous progress has been made in cataloging human sequence variations since this high-density map can offer the required tools to develop genetically based diagnostic and therapeutic tests. When additional functional polymorphisms are known, it may be attainable to develop helpful genetic markers also as personalized medicines. In the future, the main aim is to use SNPs not only to find certain aspects to be used in the future (individualized drug therapy, development of genome-based diets, etc.) but to also unveil the details of genome evolution. A number of challenges exist today in realizing the value of a high-density map of anonymous SNPs for pharmacogenomics. Concerns about the high price of genotyping are being addressed; however, it may be several years before the price of genotyping large populations is acceptable. In addition, availability of large patient populations will be crucial for discovering and validating SNPs.