CYP2C19 Genotyping

The cytochrome P450 (CYP) family of enzymes performs the primary metabolism of many drugs in the human body. One of these CYP enzymes, CYP2C19, is responsible for the metabolism of a wide variety of drugs including the anti-blood clotting drug Plavix (clopidogrel). CYP2C19 is required to convert Plavix, a prodrug, to its active form. Patients who have poor CYP2C19 activities will not effectively convert Plavix to its active form. Plavix will have low efficacy in those patients in preventing heart attack, stroke, and cardiovascular death. The Food and Drug Administration (FDA) added a boxed warning to the label of Plavix, alerting patients and doctors of the reduced effectiveness in patients who are poor metabolizers of Plavix (poor CYP2C19 activities)1. It is estimated that 2 to 14% of the population are poor metabolizers; the rate varies based on racial background.

The drug levels and antiplatelet effects of Plavix differ depending on the genotype of the CYP2C19 enzyme. The following represent the different alleles of CYP2C19 that make up a patient's genotype1:

  • The CYP2C19*1 allele has fully functional metabolism of Plavix.
  • The CYP2C19*2 and *3 alleles have no functional metabolism of Plavix. These two alleles account for most of the reduced function alleles in patients of Caucasian (85%) and Asian (99%) descent classified as poor metabolizers.
  • The CYP2C19*4, *5, *6, *7, and *8 and other alleles may be associated with absent or reduced metabolism of Plavix, but are less frequent than the CYP2C19*2 and *3 alleles.
  • A patient with two loss-of-function alleles (as defined above) will have poor metabolizer status.
  • The CYP2C19*17 allele identifies individuals who may be enhanced metabolizers of drugs. A recent report indicates increased risk for bleeding in individuals treated with Plavix who carry the *17 allele2.

The MutectorTM CYP2C19 Genotyping kit is a two tube test with simple procedures and reliable results in 3-4 hours.

ASSAY INFORMATION  

Target SNPs             Identify major alleles - *2, *3, *4, *5, *6, *7, *8, *17
Assay Platform         Capillary sequencer ABI 3100, 3700, 3130, 3500
Assay Format           Two tubes test
                                   Tube A includes alleles *2, *3, *4, *5
                                   Tube B is includes alleles *6, *7, *8, and *17
Sample Required     100-200 ng DNA from whole blood or buccal swab            

Assay workflow

ORDER INFORMATION

Cat. No. Product NameGene Alleles Interrogated SizeDocuments
GP12CYP2C19 Genotyping KitCYP2C19 *2, *3, *4, *5, *6, *7, *8, *1732 rxnManual, Product flyer

For research use only. Not for use in diagnostic procedures.

DATA
Example Results of CYP2C19 Genotyping
Tube A detects 4 variations of CYP2C19 simultaneously in a single tube:

Tube B detects 4 variations of CYP2C19 simultaneously in a single tube:

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References

  1.  http://www.fda.gov/Drugs/DrugSafety/PostmarketDrugSafetyInformationforPatientsandProviders/ucm203888.htm
  2. Sibbing D et al. (2010). Cytochrome 2C19*17 allelic variant, platelet aggregation, bleeding events, and stent thrombosis in clopidogrel-treated patients with coronary stent placement. Circulation. 121:51