Table 2.

Functional Status and Phenotypes of CYP2C19

Phenotype (frequency)GenotypeExamples of diplotype
CYP2C19 ultrarapid metabolizer (0.3–4.6% of individuals)aAn individual with 2 increased-function alleles. *17/*17
CYP2C19 rapid metabolizer (2.1–27.1% of individuals)An individual with one normal-function allele and one increased-function allele. *1/*17
CYP2C19 normal metabolizer (3.5–62.7% of individuals)An individual with 2 normal-function alleles. *1/*1
CYP2C19 intermediate metabolizer (19–45.9% of individuals)An individual with one normal-function allele and one no-function allele or one no-function allele and one increased-function allele. *1/*2
*1/*3
*2/*17
CYP2C19 poor metabolizer (1.4–57.1% of individuals)An individual with 2 no-function alleles. *2/*2
*2/*3
*3/*3
a

CYP2C19 metabolizer status frequencies are based on the range of multi-ethnic frequencies. See the CYP2C19 Frequency Tables for population-specific allele and phenotype frequencies (14).

Table is 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., and Stingl J.C. Clinical Pharmacogenetics Implementation Consortium Guideline (CPIC®) for CYP2D6 and CYP2C19 Genotypes and Dosing of Tricyclic Antidepressants: 2016 Update. 2016 Dec 20; doi: 10.1002/cpt.597. [Epub ahead of print] (15) and updated CYP2C19 Frequency Tables allele frequency ranges.
Note: The nomenclature used in this table reflects the standardized nomenclature for pharmacogenetic terms proposed by CPIC in a 2016 paper, “Standardizing terms for clinical pharmacogenetic test results: consensus terms from the Clinical Pharmacogenetics Implementation Consortium (CPIC)” (16).

From: Carisoprodol Therapy 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.