Table 6.

CPIC Assignment of likely CYP2D6 Phenotype based on Diplotype (2019)

Likely CYP2D6 metabolizer phenotypebActivity scoreGenotypeaExamples of CYP2D6 diplotype
Ultrarapid>2.25An individual carrying duplications of functional alleles*1/*1xN, *1/*2xN, *2/*2xNc
Normal1.25 to 2.25An individual carrying 2 normal function alleles or one normal function and one decreased function allele*1/*1, *1/*2, *1/*9, *1/*41, *2/*2, *1/*10
Intermediate>0 to <1.25An individual carrying one decreased function and one no function allele*1/*4, *1/*5, *41/*41, *4/*10, *4/*41, *5/*9
Poor0An individual carrying only no functional alleles*3/*4, *4/*4, *5/*5, *5/*6
a

Assignment of allele function and citations for allele function can be found on PharmGKB: Gene Reference Materials for CYP2D6 (CYP2D6 Allele Definition Table and CYP2D6 Allele Functionality Table). For a complete list of CYP2D6 diplotypes and resulting phenotypes, see the CYP2D6 Genotype to Phenotype Table. Note that genotypes with an activity score of one are classified as normal metabolizers in the online CYP2D6 genotype to phenotype table (22).

b

See the CYP2D6 Frequency Table for race-specific allele and phenotype frequencies (22) or see Gaedigk et al (23).

c

Where xN represents the number of CYP2D6 gene copies. For individuals with CYP2D6 duplications or multiplications, see supplemental data for additional information on how to translate diplotype into phenotype.

This Clinical Pharmacogenetics Implementation Consortium (CPIC) table is adapted from (3).

From: Atomoxetine Therapy and CYP2D6 Genotype

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