Pharmacogenetics

Pharmacogenetics is an area of genetic testing that assesses the genes responsible for the way a body handles and responds to medications.

A common pharmacogenetics application is related to drug metabolic pathways (how a body breaks down or metabolizes drugs). Mutations in these pathways affect an individual’s response to medication. Mutations in the genes of these pathways can cause a patient to be unable to break down a drug or to break down a drug too quickly or extensively; these mutations can make a drug ineffective or lead to an adverse drug reaction.

Indications for Testing

Pharmacogenetic testing is recommended to aid clinicians in determining the proper medication at the right dose to avoid adverse drug reactions and interactions. Pharmacogenetic test results become part of a patient's electronic health record and can be used for future medication prescribing.1 Pharmacogenetic testing should be offered to patients under the following circumstances:2
  • To provide pre-therapeutic guidance for drug and dose selection at:
    • Psychiatric facilities
    • Pain clinics
    • Oncology centers
    • Geriatrics
  • To evaluate whether an adverse drug reaction (ADR), non-standard dose requirement, or therapeutic failure could be explained by known drug-gene associations.
  • Patient has not received relief from his/her current prescription medication
  • Patient has a family or personal history of unexpected outcomes from certain medications.
  • Patient takes multiple prescriptions.
  • Patient wants to be proactive and determine his/her phenotype (drug metabolism type) prior to taking a new medication.
Testing at ARUP Laboratories
 

1. Mayo Clinic, Center for Personalized Medicine. Pharmacogenomic PGx profile service.
2. PCLS. Personalized treatment through genes.

Save Money

According to the U. S. Department of Health & Human Services, more than 770,000 injuries or deaths due to drug reactions occur in the United States each year. These events may cost a hospital up to $5.6 million each year. This number does not include the adverse drug events that cause hospital admissions, malpractice and litigation costs, or the cost of injuries to the patients.3

Pharmacogentic testing provides an opportunity to lower this number by:

  • Preventing many adverse drug events before they occur.
  • Reducing pharmacy costs for clients by optimizing dosage.
  • Decreasing the number of patient hospitalizations.
  • Improving patient compliance with their drug therapies.
  • Pharmacogenetics test results become part of a patient’s medical record. The record can be referred to when future medications are prescribed.
 

3. Agency for Healthcare Research and Quality. Reducing and preventing adverse drug events to decrease hospital costs.

Pharmacogenetics Testing

Test Number Test Name
2013098 Cytochrome P450 Genotype Panel
2014547 Cytochrome P450 2D6 (CYP2D6) 15 Variants and Gene Duplication
2012766 Cytochrome P450 2C9 (CYP2C9), 2 Variants
2012769 Cytochrome P450 2C19 (CYP2C19), 9 Variants
2012740 Cytochrome P450 3A5 Genotyping (CYP3A5), 2 Variants
2012166 Dihydropyrimidine Dehydrogenase (DPYD), 3 Variants
2007228 5-Fluorouracil (5-FU) Toxicity and Chemotherapeutic Response, 5 Mutations
2012233 Thiopurine Methyltransferase (TPMT) Genotyping, 4 Variants
2012772 Warfarin Sensitivity (CYP2C9 and VKORC1), 3 Variants
0051684 Glucose-6-Phosphate Dehydrogenase (G6PD) 2 Mutations
2007163 Glucose-6-Phosphate Dehydrogenase Deficiency (G6PD) Sequencing
2002429 HLA-B*57:01 for Abacavir Sensitivity
2012049 HLA-B*15:02 Genotyping, Carbamazepine Hypersensitivity
2008767 Opioid Receptor, Mu 1 (OPRM1) Genotyping, 1 Variant
2008426 Statin Sensitivity (SLCO1B1), 1 Variant
0051332 UDP Glucuronosyltransferase 1A1 (UGT1A1) Genotyping
2004680 Interleukin 28 B (IL28B) Associated Variants, 2 SNPs

Enhanced Report

The Cytochrome P450 Genotype Panel (ARUP test code 2013098) includes a detailed enhanced report designed to assist clinicians in the interpretation and application of the genetic test results for their patient.

Supplied in conjunction with Coriell Life Sciences, the report provides the genotype of the patient, as well as an interpretation of that genotype by an ARUP medical director. It also contains a medication summary with a list of medications that can be approached with standard precautions, those for which a dosage alteration or change in medication is recommended, and those for which an alternative is strongly suggested. The clinical evidence for each recommendation is marked as strong, moderate, or emerging. A link to GeneDose LIVE is included if clinicians need additional information. An example of this report is available on our website: Cytochrome P450 Genotype Panel enhanced report.

Experts

Gwendolyn A. McMillin, PhD
Medical Director, Toxicology and Pharmacogenetics
Yuan Ji, PhD
Medical Director, Molecular Genetics and Genomics
Pinar Bayrak-Toydemir, MD, PhD
Medical Director, Molecular Genetics and Genomics Laboratory
Hunter Best, PhD
Medical Director, Molecular Genetics Director, High Complexity Platforms—NGS
Rong Mao, MD
Section Chief, Molecular Genetics and Genomics

Resources

Ordering recommendations in pharmacogenetics are currently based on specific drugs.

Testing recommendations are endorsed/promoted by professional societies in some cases.

Video Lecture with online credits:  CME, SAM, PACE.