Pharmacogenetic Testing

GENETWORx Laboratory was created with the targeted focus of impacting and improving people’s lives by empowering them and their physicians with the information and medicinal results they need through pharmacogenomic testing.

GENETWORx Laboratory identified a gap in healthcare services between the lab and pharmacy: Every person’s body and genetic make-up is different—and therefore why shouldn’t their medications follow suit? Knowing a person’s genetic makeup helps identify drugs that their body can breakdown and metabolize. The metabolism of a drug can have important consequences on its therapeutic effect or its toxicity. For instance, whether the drug will be metabolized by the body too quickly or too slowly to be effective. Without knowing which medication will be the optimal choice, it can be trial and error for a physician—they pick a medication based on their past experience or drug prescribing information in the hope that the patient’s body responds effectively to it. Personalized medicine using pharmacogenetic testing takes some of the guesswork out of medication effectiveness.

What is Pharmacogenetics?

Pharmacogenetics refers to genetic differences in metabolic pathways which can affect an individual’s response to drugs in terms of therapeutic effect as well as adverse effects.

Taking a medication can often feel like a one-size-fits-all solution, yet it is estimated about 50% of patients do not respond effectively to the first medication prescribed by their physician.* This can cause delays in providing relief for patients, and can add additional cost to the healthcare system and a patient’s medical expenses.

GENETWORx pharmacogenetic testing, also known as DNA drug-response testing, can help determine the most effective medicine for a person’s needs and sometimes assist in dosing guidelines for a wide array of medications. It helps physicians identify potential gene-drug interactions and drug-gene-drug interactions. GENETWORx also reviews drug-drug interactions to help give a complete picture of a person’s medication therapy. Physicians will fill out a Drug Sensitivity Form (included with the pharmacogenomics DNA testing kit) and include a list of medications that their patient is currently taking or medications that the prescriber may want to consider for future use. GENETWORx also has the capability to pull all the patient’s medications that they have had filled at a pharmacy through their health insurance over the past 180 days through a third-party vendor (SureScripts).

Having a list of medications and a list of potential drug-drug interactions, gene-drug interactions, and drug-gene-drug interactions, along with this new genetic information, gives a prescriber a better understanding of why their patient may respond to a medication in a particular way. In other words: A more effective medication the first time around, eliminating the time, energy, and money wasted trying to find the “right” medication for a patient.

GENETWORx is a pharmacogenetic lab and tests 30 genes to help identify mutations that may affect a person’s metabolism and/or response to medications. Once the pharmacogenetic analysis, conducted via a simple cheek swab sample, is complete, a Personalized Medication Report is reviewed by a pharmacist at GENETWORx and prepared for the prescriber so that they can identify potential gene-drug interactions, drug-drug interactions, as well as drug-gene-drug interactions. GENETWORx reports provide a pharmacogenomic analysis along with a Personalized Medication Guide, that list medications by specialty in categories of: Use as Directed, Use with Caution, or Recommend Alternative Medication. This list can be used for helping a prescriber choose new or alternative medications for their patient. The report is a powerful tool to help healthcare providers and their patients determine the best course of treatment.

Your Patients Can Benefit from Pharmacogenetic Testing
Here’s How to Get Started:

1 Obtain a GENETWORx pharmacogenomics DNA testing kit by calling 610-726-1205.

2 Fill out the DNA Test for Drug Sensitivity Form, included with the testing kit, with appropriate patient information, test request, physician information, billing information, and diagnosis codes. Include patient medication list for analysis.

3 Use supplied buccal swabs in the testing kit to collect a patient sample.

4 Send the forms and buccal swab to GENETWORx using the pre-paid mailer included in the kit. GENETWORx will process the sample and prepare the Pharmacist reviewed report.

5 Pharmacist reviewed Reports are delivered to the provider electronically or by facsimile within 3 to 5 business days.

6 Medication management plans can now be created to deliver truly personalized medicine.

*Disclaimer: GENETWORx test kits are not intended to be a single source for medical decision-making.  GENETWORx obtains the patient’s medication history from the referring provider and/or third-party pharmacy benefit managers for its medication review.  It should be noted that the medication profile could be incomplete and is dependent upon the information provided.  Pharmacogenomic testing and the Personalized Medication Report should not be a substitute for the medical decision-making and treatment plan of the prescriber.

A Customer Testimonial

Dear Ms. Helber,
What a wonderful genetic testing service GENETWORx provides, and what great employees you have there! My husband, Mark, had genetic testing with you through his orthopedist’s office 6 years ago, as he was heading for a knee replacement in his early 50s (25 years of serious running was not a good thing). Because of his medication allergies, the orthopedist decided to do genetic testing to check on the pain meds to be prescribed. As a result, he canceled Mark’s surgery because all the meds he could prescribe for the post-surgery pain were contraindicated. Mark turned out to be a poor CYP2D6 metabolizer, and nothing was going to reduce the pain sufficiently for him to complete rehab. The orthopedist said that he didn’t want to leave Mark in worse shape than before the surgery, which was in hindsight a good thing.

All that genetic information six years ago was wonderful to have, and Stacey B. our GENETWORx pharmacist was terrific in helping us decipher it. Mark’s had more issues since, especially as he has intractable migraines and is constantly taking pain meds, so we and his latest neurologist decided to redo the genetic testing. Stacey said GENETWORx had increased the number of genes it tests for. Another super-helpful choice on our part! When we had access to it, we both thoroughly read through and highlighted specific meds he should avoid, and yep, he’d been prescribed some of them in the intervening six years, with less than positive results.

Stacey has been a treasure during the past several months, helping us check on additional meds, explaining ProDrugs versus non ProDrugs, and just generally being amazing. At this point there have been a number of emails between us, and I can really tell that she’s not only an excellent pharmacist but a truly wonderful person, and a great asset to you and GENETWORx. One critical thing, especially during these times of working remote, is that Stacey can write complete, thoroughly explanatory emails, which is not a common skill. We’ve been really appreciative to have her assistance and her kindness as we negotiate Mark’s worsening health.

The last months have been a difficult time for everyone, so Mark and I both immensely appreciate the services you still provide at GENETWORx. Thanks again, keep up the good work, and stay well.”

—Lynn

Medication Management Test Menu

Cytochrome P450 Enzymes: The Cytochrome P450 enzyme system is one of several metabolic systems which plays a major role in the metabolism of drugs. A drug that is metabolized by a certain enzyme is a substrate of that enzyme. Some drugs are also prodrugs of a certain enzyme, meaning it becomes “active” in the body after it is metabolized. Mutations in the specific enzymes can cause individuals to metabolize drugs at different rates. Metabolic rates are classified for each enzyme as Normal Metabolizer, Rapid Metabolizer, Intermediate Metabolizer and Poor Metabolizer.

Gene Description
Cytochrome P450 Enzymes The Cytochrome P450 enzyme system is one of several metabolic systems which plays a major role in the metabolism of drugs. A drug that is metabolized by a certain enzyme is a substrate of that enzyme. Some drugs are also prodrugs of a certain enzyme, meaning it becomes “active” in the body after it is metabolized. Mutations in the specific enzymes can cause individuals to metabolize drugs at different rates. Metabolic rates are classified for each enzyme as Normal Metabolizer, Rapid Metabolizer, Intermediate Metabolizer and Poor Metabolizer.
CYP1A2 This gene encodes for the formation of CYP1A2 enzymes influencing variability in metabolism of approximately 9% of medications. Some examples of CYP1A2 substrates are caffeine, clozapine, cyclobenzaprine, lidocaine, olanzapine, propranolol, ropivacaine, tizanidine, zileuton.
CYP2B6 This gene encodes for the formation of CYP2B6 enzymes influencing variability in metabolism of approximately 7% of medications. Some examples of CYP2B6 substrates are bupropion, efavirenz, irinotecan, ifosfamide, methadone, cyclophosphamide, ketamine, meperidine, nevirapine, propofol, selegiline, testosterone.
CYP2C19 This gene encodes for the formation of CYP2C19 enzymes influencing variability in metabolism of approximately 10 to 15% of medications. Some examples of 2C19 substrates are esomeprazole, lansoprazole, citalopram, escitalopram, amitriptyline, diazepam, phenytoin, carisoprodol, clopidogrel, sertraline, pantoprazole, moclobemide, imipramine, voriconazole.
CYP2C8 This gene encodes for the formation of CYP2C8 enzymes influencing variability in metabolism of approximately 5% of medication. Some examples of CYP2C8 substrates are amiodarone, paclitaxel, pioglitazone, rosiglitazone, repaglinide, torsemide.
CYP2C9 This gene encodes for the formation of CYP2C9 enzymes influencing variability in metabolism of approximately 15% of medication. Some examples of CYP2C9 substrates are meloxicam, losartan, glipizide, glyburide, phenytoin, warfarin and torsemide.
CYP2D6 This gene encodes for the formation of CYP2D6 enzymes influencing variability in metabolism of approximately 25-30% of medication. Some examples of CYP2D6 substrates are fluoxetine, paroxetine, aripiprazole, risperidone, duloxetine, amphetamine, metoprolol, tamoxifen, codeine, oxycodone, and tramadol.
CYP3A4/CYP3A5  This gene encodes for the formation of CYP3A4/5 enzymes influencing variability in metabolism of approximately 40% of medications. Some examples of CYP3A4/5 substrates are clarithromycin, clonazepam, diazepam, etravirine, loratadine, diltiazem, simvastatin, fentanyl, carbamazepine, cilostazol, oxycodone, aripiprazole, salmeterol, tamoxifen, trazodone, vemurafenib, zolpidem.

Additional Pharmacokinetic and Pharmacodynamic Genes

Gene Description
ABCB1 ABCB1 (ATP binding cassette subfamily B) encodes for the formation of intestinal efflux transporter P-glycoprotein and is a major contributor in the intestinal absorption of ABCB1 substrates. Poor and intermediate ABCB1 phenotypes may have an increased likelihood of therapeutic failure compared to patients with a normal phenotype and taking ABCB1 substrates. Example Substrates: copidogrel, aliskiren, ambrisentan, colchicine, dabigatran etexilate, digoxin, everolimus, fexofenadine, imatinib, lapatinib, maraviroc, nilotinib, posaconazole, ranolazine, saxagliptin, sirolimus, sitagliptin, talinolol, tolvaptan, topotecan.
ABCG2 ABCG2 (ATP binding cassette subfamily G2) encodes for the formation of intestine, liver, placenta, and the blood–brain barrier efflux transporters in the form of homodimers in the plasma membrane and actively extrudes a wide variety of chemically unrelated compounds from the cells. This protein protects our cells and tissues against various xenobiotics. Example Substrates: daunorubicin, doxorubicin, topotecan, rosuvastatin, sulfasalazine
ADRA2A ADRA2A (Adrenoceptor Alpha 2A) gene plays a critical role in regulating neurotransmitter release from sympathetic nerves and from neurons that release the hormone and neurotransmitter norepinephrine in the central nervous system. Variants in the gene have been linked to the clinical effectiveness of ADHD medications. Additional studies have shown other variants associated with an increased risk for hypertension. Variants in ADRA2A are thought to be present in a quarter of the caucasian population.
APOE APOE (Apolipoprotein E) gene encodes for the formation of apolipoprotein E which combines with fats (lipids) in the body to form lipoproteins. Lipoproteins are responsible for forming cholesterol and other fats found through the bloodstream. Studies have shown individuals who carry one or more copies of APOE-4 have a reduced therapeutic response to lipid-lowering medications (statins). The APOE-4 allele has shown to have an increased risk of high LDL cholesterol and both cardiovascular disease and Alzheimer’s disease.
COMT Catechol-O-Methyltransferase (COMT) is an enzyme that inactivates catecholamines, such as epinephrine, norepinephrine and dopamine. COMT regulates cognitive function, memory, mood and pain perception. Up to 60% of depressed patients do not respond completely to antidepressants and up to 30% do not respond at all. A variety of drugs, such as nicotine replacement therapy (NRT), entacapone, opioids, SSRIs and antipsychotics, may be directly or indirectly impacted by the change in catecholamines inactivation.Catechol-O-Methyltransferase (COMT) is an enzyme that inactivates catecholamines, such as epinephrine, norepinephrine and dopamine. COMT regulates cognitive function, memory, mood and pain perception. Up to 60% of depressed patients do not respond completely to antidepressants and up to 30% do not respond at all. A variety of drugs, such as nicotine replacement therapy (NRT), entacapone, opioids, SSRIs and antipsychotics, may be directly or indirectly impacted by the change in catecholamines inactivation.
CYP1A2 This gene encodes for the formation of CYP1A2 enzymes influencing variability in metabolism of approximately 9% of medications. Some examples of CYP1A2 substrates are: Caffeine, amitriptyline, clozapine, cyclobenzaprine, naproxen, propranolol, ropivacaine, tizanidine, verapamil, zileuton
CYP2B6 This gene encodes for the formation of CYP2B6 enzymes influencing variability in metabolism of approximately 7% of medications. Some examples of CYP2B6 substrates are: bupropion, efavirenz, ifosfamide, methadone, sorafenib, cyclophosphamide, Ketamine, Meperidine, nevirapine, nicotine, propofol, selegiline, sertraline, tamoxifen, Testosterone…this list is not all inclusive
CYP2C19 This gene encodes for the formation of CYP2C19 enzymes influencing variability in metabolism of approximately 10 to 15% of medications. Some examples of 2C19 substrates are: esomeprazole, lansoprazole, amitriptyline, clomipramine, diazepam, phenytoin, carisoprodol, chloramphenicol, clopidogrel, hexobarbital, mephobarbital, moclobemide, primidone, propranolol, voriconazole
CYP2C8 This gene encodes for the formation of CYP2C8 enzymes influencing variability in metabolism of approximately 5% of medication. Some examples of CYP2C8 substrates are: amodiaquine, paclitaxel, repaglinide, sorafenib, torsemide
CYP2C9 This gene encodes for the formation of CYP2C9 enzymes influencing variability in metabolism of approximately 15% of medication. Some examples of CYP2C9 substrates are: meloxicam, losartan,  angiotension receptor blockers (ARB), sulfonylureas, and torsemide.
CYP2D6 This gene encodes for the formation of CYP2D6 enzymes influencing variability in metabolism of approximately 25-30% of medication. Some examples of CYP2D6 substrates are: fluoxetine, apriprazole, Antipsychotics, mexiletine, metoprolol, Beta Blockers, codeine, tramadol and many other drugs
CYP3A4/5 This gene encodes for the formation of CYP3A4/5 enzymes influencing variability in metabolism of approximately 40% of medications. Some examples of CYP3A4/5 substrates are: clarithromycin, telithromycin, clonazepam, etravirine, Claritin, Diltiazem, Simvastatin, fentanyl, boceprevir, carbamazepine, cilostazol, risperidone, salmeterol, tamoxifen, trazodone, vemurafenib, zolpidem
DBH Dopamine Beta-Hydroxylase (DBH) gene encodes for the formation dopamine beta-hydroxylase protein. DBH protein catalyzes the hydroxylase of dopamine to norepinephrine and is primarily located in the adrenal medulla and in postganglionic sympathetic neurons. Variations in the DBH gene have been shown to be a risk factor for psychiatric disorders and addiction.
ANKK1/

DRD2/Taq1A

ANKK1 gene is linked to dopamine receptor D2 (DRD2). Dopamine (DA) is a neurotransmitter in the brain, which controls feeling of wellbeing. This sensation results from dopamine and other neurotransmitters such as serotonin, opioids, and other brain chemicals.

Dopamine increases the motivation for food cravings and appetite mediation. The DRD2/ANKK1-Taq1A polymorphism modulates the density of the DRD2 dopamine receptors. Carriers of the A1 allele have shown up to 30% reduced receptor capacity, correlating to a predisposition for individuals to seek addictive behaviors or substances to compensate this deficiency in the dopaminergic system; Examples include binge eating (e.g. fat, refined carbohydrates, salt, caffeine, etc.) and compulsive and impulsive behaviors (e.g. sexual activity, gambling and use of alcohol, drugs, opiates, tobacco etc.).

DPYD This gene encodes the dihydropyrimidine dehydrogenase protein, the initial and rate limiting enzyme in the three-step pathway of uracil and thymidine catabolism and the pathway leading to the formation of beta-alanine. The DPYD protein is responsible for degrading fluoropyrimidines, such as 5-fluorouracil, capecitabine, and tegafur. Decreased DPYD activity is associated with a greater than four-fold risk of severe or fatal toxicity from standard doses of 5FU.
F2 The Factor II variant G20210A indicates increased risk of blood clotting disorders. Certain hormonal contraceptives such as norelgestromin and ethynyl estradiol (EVRA) are contraindicated in women with the Factor II or Factor V mutation due to the risk of arterial or venous thrombosis.
Factor V Leiden The Factor V variant indicates risk of blood clotting disorders. Factor V Leiden (or rs6025) is associated with an approximately 300% increased risk in heterozygotes and an up to 8000% increased risk in homozygotes. The Royal Dutch Pharmacists Association-Pharmacogenetics Working Group recently cautioned against the use of estrogen-containing oral contraceptives for women with the FV mutation.
GRIK4 GRIK4 (glutamate receptor, ionotropic, kainate 4) is the gene that encodes KA1, a type of neurotransmitter receptor subunit that joins together with other subunits to form glutamate receptors. These receptors are located on cells in the brain and are involved in enhancing cell-cell communication, which may play a role in major depressive disorder. This type of receptor primarily binds glutamate, a major neurotransmitter involved in developmental growth, learning and memory. Although the effect of variations in GRIK4 on KA1 function and expression are not fully known, KA1 may play a role in modulating the therapeutic effect of antidepressants. Mutations in GRIK4 may impact patients with major depressive disorder who take citalopram. Patients being considered for citalopram initiation or who have experienced treatment resistance or failure with citalopram should be considered for GRIK4 testing.
HTR2A HTR2A is a post-synaptic serotonin receptor that binds serotonin and is involved in amplification of excitatory signals to other neurons in the brain. Polymorphisms of this gene may affect antidepressant and antipsychotic response and risk of adverse effects. HTR2A polymorphisms can help predict which patients may be more likely to experience SSRI-induced adverse effects and provide supplemental information to determine if patients will adequately respond to therapy.
HTR2C HTR2C is a G-protein coupled serotonin receptor located on the X chromosome. Mutations in this receptor may be useful in predicting which patients are at risk for adverse events from drugs such as olanzapine.
IL28B IL28B, also called interferon, lambda 3, is the strongest baseline predictor of response to PEG-interferon-alpha-containing regimens in HCV genotype 1 patients. Patients with the favorable response genotype increased likelihood of response (higher SVR rate) to PEG-interferon-alpha-containing regimens as compared to patients with unfavorable response genotype. Consider implications before initiating PEG-IFN alpha and RBV containing regimens.
ITGB3 ITGB3 encodes the gene for beta 3 integrin. Mutations in this gene influence the efficacy of drugs such as clopidogrel.
MTHFR Reduced enzyme activity of MTHFR is a genetic risk factor for hyperhomocysteinemia. Hyperhomocysteinemia patients have a moderate risk for DVT and blood clots. Avoid estrogen therapy for control of menopausal symptoms. MTHFR Homozygous Variant (This stands alone when FII/FV are normal but is additive with any variant and should be red)
OPRK1 Kappa 1 opioid receptor (OPRK1) is a pharmacodynamic receptor that is partly responsible for opioid effectiveness and is associated with pain sensitivity, substance dependence and abuse. The most analyzed genetic variants have shown an association with opioid effectiveness to oxycodone leading to decreased likelihood of treatment failure.
OPRM1 Mu 1 opioid receptor (OPRM1) is a pharmacodynamic receptor that is partly responsible for opioid effectiveness and is associated with pain sensitivity, substance dependence and abuse. The most analyzed genetic variants have shown an association with opioid effectiveness, naltrexone efficacy in the treatment of alcoholism and addiction risk to opioids, including heroin. Patients beginning naltrexone treatment for alcohol dependence would be good candidates for OPRM1 testing. Testing can also help predict opioid response and dose requirements. Testing can also help assess opioid addiction risk.
SLCO1B1 SLCO1B1 (also known as OAT1B1) encodes for the formation of influx transporter that moves drugs into cells. Variations in SLCO1B1 may affect the blood levels of drugs that are substrates for this transporter. Some examples of SLCO1B1 transported drugs are: atorvastatin, bosentan, ezetimibe, fluvastatin, glyburide, SN-38 (active metabolite of irinotecan), rosuvastatin, simvastatin acid, pitavastatin, pravastatin, repaglinide, rifampin, valsartan, olmesartan
UGT1A1 Uridine diphosphate (UDP)-glucuronosyl transferase 1A1 (UGT1A1) is responsible for bilirubin conjugation with glucuronic acid. UGT1A1 is a pharmacogene and patients with reduced UGT1A1 enzyme activity are at risk for adverse outcomes with certain drugs. The FDA drug labels for nilotinib, pazopanib, and belinostat all contain warnings for an increased risk (incidence) of adverse outcomes in patients who have UGT1A1 alleles associated with reduced activity.
UGT2B15 UDP-glucuronosyltransferase 2B15 is an enzyme that in humans is encoded by the UGT2B15 gene. The UGTs are of major importance in the conjugation and subsequent elimination of potentially toxic xenobiotics and endogenous compounds. Polymorphisms have been associated with variation in drug metabolism, including some drugs used for mental health disorders, PPAR agonist (Thiazolidinediones), and clearance of oxazepam or lorazepam.
VKORC1 Vitamin K epoxide complex subunit 1 (VKORC1) is the enzyme that activates Vitamin K. Mutations in VKORC1 are associated with deficiencies in vitamin-K-dependent clotting factors. A particular VKORC1 variant (-1939G>A) leads to increased sensitivity to warfarin. VKORC1 mutation accounts for 25-44% of warfarin dose variability and is typically tested for at the same time as 2C9 when warfarin is being considered.
Cytochrome P450 2C19 This test detects variants in genes which may affect an individual’s response to approximately 5% – 10% of all medications.
Cytochrome P450 2C9 & VKORC1 This test detects variants in genes which may affect an individual’s response to approximately 15% of all medications (including Warfarin Sensitivity via 2C9 and VKORC1).
Cytochrome P450 2D6 This test detects variants in genes which may affect an individual’s response to approximately 25% of all medications.
Cytochrome P450 3A4 & 3A5 This test detects variants in genes which may affect an individual’s response to approximately 40% – 45% of all medications.
Factor II Prothrombin Genetic Profiling This test detects a genetic change in the Factor II gene called Factor II Prothrombin. Patients with this Prothrombin variant are at an increased risk of blood clot formation (thrombosis) when exposed to other risk factors such as smoking, pregnancy, obesity, oral contraceptive use, and immobility. The risk is approximately 3-10 times higher in individuals who have one copy of the genetic variant. The risk in people who carry two copies of the genetic variant is unknown. Individuals who do not have a Factor II Prothrombin mutation may still be at increased risk. Other changes in the Factor II gene that were not tested for, changes in other genes, and non-genetic factors may still increase your risk for thrombosis.
Factor V Leiden Mutation Test This test detects a genetic change in the Factor V gene called Factor V Leiden. Individuals who have this variant are at an increased risk of blood clot formation. This risk is approximately 2-10 times higher in individuals who have one copy of the genetic variant, and greater than 10 times higher for individuals who carry two copies of the genetic variant. Individuals who do not have the Factor V Leiden mutation may still be at increased risk. Other changes in the Factor V gene that were not tested for, changes in other genes, and non-genetic factors may still increase your risk for thrombosis.
MTHFR Mutation Testing This test detects two genetic changes in the MTHFR gene. Individuals who are found to have two mutations are at an increased risk for serious blood clot formation. Individuals who have only one or no copies of either genetic change in the MTHFR gene may still be at increased risk. Other changes in the MTHFR gene that were not tested for, changes in other genes, and non-genetic factors may still increase your risk for thrombosis.
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