Table 3:

Assignment of CYP2C19 phenotypes by CPIC

PhenotypeGenotypesExamples of diplotypes
CYP2C19 ultrarapid metabolizer
(approximately 2–35% of patients)a		An individual carrying two increased function alleles *17/*17
CYP2C19 rapid metabolizer
(approximately 2–30% of patients)		An individual carrying one normal function allele and one increased function allele *1/*17
CYP2C19 normal metabolizer
(approximately 35–50% of patients)		An individual carrying two normal function alleles *1/*1
CYP2C19 Intermediate metabolizer
(approximately 18–45% of patients)		An individual carrying one normal function and one no function allele
or one no function allele and one increased function allele		 *1/*2
*1/*3
*2/*17b
CYP2C19 Poor metabolizer
(approximately 2–15% of patients)		An individual carrying two no function alleles *2/*2
*2/*3
*3/*3
a

For population-specific allele and phenotype frequencies, please see (2).
b The predicted metabolizer phenotype for the *2/*17 genotype is a provisional classification.

Table has been adapted from Hicks J.K., Sangkuhl K., Swen J.J., Ellingrod V.L., Müller D.J., Shimoda K., Bishop J.R., Kharasch E.D., Skaar T.C., Gaedigk A., Dunnenberger H.M., Klein T.E., Caudle K.E. Clinical Pharmacogenetics Implementation Consortium Guideline (CPIC®) for CYP2D6 and CYP2C19 Genotypes and Dosing of Tricyclic Antidepressants: 2016 Update. Clinical pharmacology and therapeutics. 2016 Dec 20 [Epub ahead of print] (2).

From: Amitriptyline Therapy and CYP2D6 and CYP2C19 Genotype

Cover of Medical Genetics Summaries
Medical Genetics Summaries [Internet].
Pratt VM, Scott SA, Pirmohamed M, et al., editors.
Copyright Notice

All Medical Genetics Summaries content, except where otherwise noted, is licensed under a Creative Commons Attribution 4.0 International (CC BY 4.0) license which permits copying, distribution, and adaptation of the work, provided the original work is properly cited and any changes from the original work are properly indicated. Any altered, transformed, or adapted form of the work may only be distributed under the same or similar license to this one.

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.