Chromosomes were first discovered in the late 1800s. By the early 1900s, chromosomes were linked to inherited diseases and, starting in the 1950s, discoveries led to genetic tests for certain conditions. Genetic testing is the analysis of DNA or RNA to identify changes in gene sequence, gene expression, the presence of gene products (proteins), or for analysis of chromosomes. Only a few research laboratories were capable of testing and there were few commercial laboratories.
Today, genetic testing is available directly to the consumer and thousands of tests are available. They are used for everything from diagnosis, estimating risk, carrier screening, paternal testing, and prenatal and newborn screenings. Genetic testing can also be performed in order to determine whether a drug is suitable for a patient, and what the best dosage would be. The tests are easily performed with little to no discomfort to the patient. They can be conducted on a sample of blood, hair, skin, saliva, amniotic fluid, or other tissue.
Just as diet, exercise, environment, stress, and many other factors influence individuals differently, so do therapies and medications. Some people may find much success with a medication, while the same medication is ineffective or even causes a negative reaction in someone else. Scientists are finding more and more that these differences are related to our genetics; how our genes “process” each of these things and influence other bodily processes, chemicals, pathways, and reactions.
Scientists estimate that, in the human race, there are at least 15 million genetic polymorphisms and an undefined subgroup of variations in normal and disease traits. Polymorphisms are basically genetic variations, meaning that there are two or more alternative forms of the two alleles that make up the same segment of DNA. The most obvious example of this type of genetic variation is the separation into male and female. Another is blood type.
According to the article “The Importance of Race and Ethnic Background in Biomedical Research and Clinical Practice” as published in the New England Medical Journal, “…the change of only a single base pair is required to cause many well-known inherited diseases, such as sickle cell disease, or to increase the risk of common disorders, such as Alzheimer’s disease.”
Some disorders, called Mendelian disorders, are controlled by a single gene mutation that is inherited. Examples of these include sickle-cell anemia, Tay-Sachs disease, cystic fibrosis, and xeroderma pigmentosa.
Genetic testing in the research environment is performed for the purposes of “finding unknown genes, learning how genes work, developing tests for future clinical use, and advancing our understanding of genetic conditions,” according to the U.S. National Library of Medicine’s Guide to Understanding Genetic Conditions. It is used in clinical trials for diagnostic, prognostic, or predictive purposes with the goal to improve the success of trials through:
• providing a better understanding of how genes can cause or influence disease;
• developing targeted therapies;
• improving the outcomes of therapies; and
• reducing the number of adverse events such as negative drug reactions.
Some clinical trials require participants to possess the genetic mutation linked to a particular disease. Genetics can explain the differences in responses to treatments/medications and can make it easier to determine why some people benefit and others don’t. Testing can also help identify other family members who may qualify for a trial or for a particular therapy. All of this leads to results that can be used to help make more specific decisions about medical care, tailoring therapies based on genetics to enhance effectiveness and reduce adverse events by matching patients’ genetic information to the most effective treatment.
The National Human Genome Research Institute of the National Institutes of Health states that the utilization of genetic data is ushering in a “new era in medicine—one where a more profound understanding of the biological basis of disease will pave the way for more effective ways to diagnose, treat and prevent illness.”
Meridien Research is currently conducting studies that include genetic testing. For more information or to see if you or someone you know may qualify to participate, please contact us today at 1-407-644-1165.