The GeneSight Psychotropic test analyzes clinically important genetic variations in your DNA. The results of the test are intended to help your clinician understand how your genetic makeup may impact the way your body breaks down or responds to certain medications used to treat depression, anxiety, ADHD and other psychiatric conditions.
Since a person’s genetics do not change over time, their GeneSight results are expected to be accurate throughout the entirety of their life.
However, genetics is just one piece of the puzzle, and other factors such as your medical history may impact your outcomes with a medication. Here, we take a closer look at the most common questions we receive about how a person’s medical history might impact the results of the GeneSight Psychotropic test.
Existing medications & the GeneSight test
The medications a person has taken or is currently taking do not impact the genetic results on the GeneSight test. Since a person’s genes cannot be changed by medication, the genetic results of the GeneSight test will not be altered by your medication usage. Accordingly, you do not have to stop taking your medication to get accurate genetic results.
However, it is possible that certain medications a patient is taking may affect their outcomes with other medications. This is called a drug-drug interaction, which is one factor that needs to be taken into consideration by a clinician when prescribing medication.
If I smoke cigarettes or marijuana, could it impact my GeneSight results?
Yes, possibly. If you smoke cigarettes or marijuana, it may have an impact on how certain mental health medications are metabolized by your body alongside certain genetic variation. On the GeneSight report, smoking is defined as the daily inhalation of burning plant material, such as cigarettes and marijuana. This definition excludes vaping and e-cigarettes.
Smoking can increase the activity of CYP1A2, a gene included on the GeneSight test, in certain patients who have the highly inducible variant found in this gene. This means that smoking can cause some patients to break down (metabolize) certain medications more quickly than normal.
For this reason, the GeneSight report will include non-smoker and smoker results pages for patients with this CYP1A2 genetic variation. Clinicians and patients should refer to the correct medication pages based on the patient’s smoking status when using the GeneSight report to help inform treatment.
Will certain medical conditions, or procedures, impact my GeneSight results?
Some medical conditions or procedures may impact GeneSight test results. The following medical conditions or procedures are not expected to interfere with the accuracy of the GeneSight genetic testing results:
- Having had chemotherapy for cancer treatment in the past
- Having celiac disease
- Taking weekly plasma replacement products
- Having had a traumatic brain injury
However, some procedures and conditions may impact the genetic results of the GeneSight test. These are detailed below.
Bone Marrow Transplant
Bone Marrow Transplant (BMT) is a “procedure that infuses healthy blood-forming stem cells into your body to replace bone marrow that’s not producing enough healthy blood cells. A bone marrow transplant is also called a stem cell transplant,” according to an article on the Mayo Clinic website. “You might need a bone marrow transplant if your bone marrow stops working and does not produce enough healthy blood cells.”
If the lab sees abnormal genotype results, they try to differentiate between several possibilities, one of which is that the patient may have had a BMT. In these cases, the lab usually requests a new sample, and they will ask if the patient had a BMT. If the answer is yes, they ask that the patient rinse their mouth with water a couple of times before collecting the sample as this should remove some of the surface blood cells and allow them to obtain preferentially patient cells and likely discern a patient genotype.
Accordingly, your healthcare provider should be aware of a bone marrow transplant when considering the results of the GeneSight test. When we are aware that a patient has had a bone marrow transplant, we add a comment to the GeneSight report stating this. The results as a whole should be interpreted by your healthcare provider with caution.
Liver Transplants
“A liver transplant is a surgery that removes a liver that no longer functions properly (liver failure) and replaces it with a healthy liver from a deceased donor or a portion of a healthy liver from a living donor,” according to the Mayo Clinic website.
When the liver is transplanted, it retains the DNA of the donor. However, the GeneSight test evaluates the DNA of the recipient.
Specifically, the GeneSight test analyzes genetic variation found in 14 genes that may impact a patient’s outcomes with certain medications. These genes include nine pharmacokinetic genes and five pharmacodynamic genes:
- Pharmacokinetic (PK) genes are involved in how the body metabolizes, or breaks down, a particular medication through specific drug metabolizing enzymes mostly found in the liver.
- Pharmacodynamic (PD) genes provide information on how your DNA may impact your likelihood of response or risk for side effects with some medications.
So, back to liver transplants and how it could impact GeneSight results. As mentioned previously, when the liver is transplanted, it retains the DNA of the donor. Yet, through a simple mouth swab, the GeneSight test analyzes the DNA of the recipient.
Therefore, the liver transplant could impact the results in the pharmacokinetic portion of the test result, which provides information about how the body may break down certain medications. Because this happens primarily in the liver, the PK portion of the test result may not be accurate for a liver transplant recipient.
However, the GeneSight test includes pharmacodynamic genes, which provide information on the likelihood of response or risk of side effects with certain medications. Since these results will be accurate for liver transplant patients, clinicians can consider ordering GeneSight testing if they believe benefit can be gained from the pharmacodynamic gene results.
The interpretive pages at the beginning of the GeneSight report (where medications are categorized into the green “use as directed,” yellow “moderate gene-drug interaction,” and red “significant gene-drug interaction” columns) are dependent on both pharmacokinetic and pharmacodynamic genes results.
Accordingly, these interpretative pages should not be used by clinicians to inform medication decisions in the cases of patients with liver transplants.
Chromosomal Abnormalities
According to the National Human Genome Research Institute Chromosome Abnormalities Fact Sheet, “Chromosomes are the structures that hold genes.” The fact sheet explains that while typically each human cell contains 23 pairs of chromosomes, there are cases where numerical or structural abnormalities may occur in an individual’s chromosomes.
“A numerical abnormality means an individual is either missing one of the chromosomes from a pair or has more than two chromosomes instead of a pair,” according to the fact sheet. “A structural abnormality means the chromosome’s structure has been altered in one of several ways.”
The structural alteration can mean that a portion of the chromosome is either missing, duplicated, transferred to another chromosome, or has broken off and either reattached itself upside down or formed a ring.
It is possible that certain chromosomal abnormalities may affect DNA sample analysis, and potentially the results for certain genes. It will be dependent on the chromosome and the location of the abnormality.
Relatives and Identical Twins
The GeneSight test evaluates a person’s unique genetic composition. Because your genes and your relative’s genes will not be exactly the same, a medication that works for them may not work for you, and your GeneSight test resultswill likely not be exactly the same.
However, identical twins are expected to have the same DNA, and therefore the results of the GeneSight test are expected to be identical for each twin. It is still recommended that each twin get their own GeneSight test done for their records. Additionally, having their own GeneSight test is important for the clinicians treating them.
For fraternal/non-identical twins, GeneSight test results are expected to be different since they have different DNA.
The GeneSight test can be one part of a clinician’s evaluation
Pharmacogenomic testing, like the GeneSight test, is intended to provide insight on how an individual’s genetic variation may affect outcomes with certain medications and should be used in conjunction with other clinical factors, clinician expertise and judgment. Therefore, pharmacogenomic tests like GeneSight are intended to be ordered by and used only in consultation with a healthcare provider who can prescribe medications.
For more information on the GeneSight test, visit genesight.com, email us at medinfo@myriad.com, or phone 855.891.9415.
This document is for educational purposes related to pharmacogenomics and personalized medicine only and should not be considered medical advice. The information is based on scientific opinion from industry experts and is intended to provide additional information.
The GeneSight test must be ordered by and used only in consultation with a healthcare provider who can prescribe medications. As with all genetic tests, the GeneSight test results have limitations and do not constitute medical advice. The test results are one element of a clinician’s decision-making process, which must be tailored to the specific circumstances of each patient. Do not make any changes to your current medications or dosing without consulting your clinician. Not all patients who receive the GeneSight test will experience improved outcomes and/or cost savings.
These materials may be changed, improved, or updated without notice. Myriad Genetics is not responsible for any errors or omissions contained in third party content. We encourage you to contact us for specific scientific advice regarding our GeneSight® tests. You may print a copy of this document for your own personal noncommercial use. You may not copy any part of this document for any other purpose, and you may not modify any part of this document without the permission of Myriad Genetics.
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