Pharmacogenetics is a field of study of genetics that is still young and that began to expand in the first half of the 2000s. This fact is reflected in the increase in the number of articles published per year that have the words “Pharmacogenetics” or “Pharmacogenomics” in their title. In order to explain in detail what pharmacogenetics is, it is necessary to introduce two basic concepts of genetics, genes and genetic variants.
Human DNA contains some 20,000 genes which make up what our instruction book would represent. These instructions are made up of an alphabet of 4 letters “A”, “T”, “C” and “G” whose objective is to manufacture proteins that are in charge of the different functions that each of the cells of our organism presents. Sometimes the sense of these instructions can change due to a change, addition, or deletion of a letter, which can result in a protein with altered or deficient functions. These errors are called genetic variants or mutations, and each of us has a different combination of these variants that makes us unique and defines genetic variation between people.
Genetic variants can occur in proteins responsible for metabolizing some drugs, which can lead to changes in the way these drugs are absorbed by the body, in how they are metabolized, or in the time it takes for them to take effect. Sometimes, these changes can generate a protein that is incapable of metabolizing the drug, which can produce severe adverse effects and compromise the health and, sometimes, the life of a person. And this is where the role of pharmacogenetics is fundamental, since its main objective is to study the relationship between the changes that can occur in genes and the response to certain drugs. These associations can play an important role in determining the way to use a type of drug, from adjusting the dose to even avoiding its use. Therefore, the success of a therapy may be conditioned to the prior performance of a pharmacogenetic study.
To contextualize the importance of pharmacogenetics, in Spain 45% of the entire population claims to have taken some type of medication in the last two weeks prior to the time of the survey carried out by the National Institute of Statistics on medication. This data is doubled in people over 75 years of age. Knowing these data, our team has worked to develop a pharmacogenetic test as complete as possible, analyzing the information on genetic variants in 16 genes associated with the metabolism of more than 60 different drugs, including many commonly used, such as ibuprofen or omeprazole, among others. The information included in our test is based on the most rigorous levels of scientific evidence according to the PharmGKB database. The levels of evidence are an indicator of how well-founded the association of certain genetic variants with the response to a type of drug is. In total there are 4 levels of evidence, where briefly, levels 1 and 2 comprise those gene-drug associations that meet at least one of the following requirements:
- There are clinical guidelines for specific dose recommendations for a given genetic variant.
- There is an annotation of the drug and the genetic variant approved by the Food and Drug Administration (FDA).
- There is at least one scientific publication that supports dosage recommendations according to the type of genetic variant.
- Associations of genetic variants and drug response are supported by at least two independent scientific publications.
For levels 3 and 4, there is an association between the variants and their effect on drug metabolism, but either there are not enough scientific publications to support it, or this association is supported by very preliminary experiments, or, finally, there are several publications. who question this association. The annotations in these last two levels are the most numerous and with time and the increase in the number of studies in this field, some will pass to levels 1 or 2.
What benefits can a pharmacogenetic test bring me?
As we mentioned earlier, our genetics can determine how we respond to a drug and each of us is genetically different, so the use of a drug cannot be generalized, especially when its use could make the difference between curing or worsening a condition or pathology. Therefore, a pharmacogenetic test can give you the advantage of obtaining a personalized therapy that adapts to your genetics, increasing the chances of success of the therapy and minimizing adverse effects as much as possible.
Despite the fact that the application of pharmacogenetics in clinical practice is still relatively new, there are cases where its use has been highly relevant. For example, the use of mercaptopurine in patients with acute lymphoblastic leukemia, which mainly affects infants. Mercaptopurine is a drug that is used as an anticancer in chemotherapy sessions. This molecule is metabolized by a protein known as TPMT. The action of TPMT prevents the accumulation of mercaptopurine in the bloodstream, which could lead to a severe decrease in the immune system, known as myelosuppression. Myelosuppression, in turn, can cause anemia, infection-like symptoms, or thrombocytopenia, and can be fatal. The presence of genetic variants can compromise the function of the TPMT protein and consequently increase the risk of accumulating mercaptopurine in the bloodstream. Currently, in the United Kingdom, 67% of doctors who prescribe mercaptopurine request to evaluate the variants in the TPMT gene before its administration, avoiding consequences that can be fatal due to the use of the treatment.
What is the future of pharmacogenetics?
As new scientific studies are carried out around pharmacogenetics, a greater number of drugs and genetic variants will be associated, allowing optimal use of drugs. The AboutMe Pharmacogenetic test is available so that your doctor can give you guidelines on the use of some medications in a personalized way. In this way, you will take full advantage of current knowledge about the interaction of your genetics with some drugs, and thus access a new revolutionary medicine where genetics joins clinical practice to carry out the best therapy at an individual level. This test is carried out using a simple saliva sample, with the convenience of managing the entire process online, requesting a sample extraction kit that the ADN Institut laboratory sends and collects at no cost. Genetic information is no longer inaccessible to the majority, now it comes to your home.