Table 1.
CPIC Phenotype and Genotype Definitions with Associated Enzyme Activity
| CYP2C19 Phenotype | Genotype | Diplotype Examplesb | Enzyme Activity |
|---|---|---|---|
| Ultrarapid Metabolizers (UMs) | Two increased function alleles | *17/*17 | Markedly increased compared to NM |
| Rapid Metabolizers (RMs) | One normal function and one increased function allele | *1/*17 | Increased compared to NM |
| Normal Metabolizers (NMs) | Two normal function alleles | *1/*1 | Normal |
| Intermediate Metabolizers (IMs) | One normal function and one no function allele; or One no function and one increased function allele |
*1/*2, *1/*3, *1/*8, *2/*17, *8/*17 | Decreased compared to NM |
| Likely Intermediate Metabolizers (IMs)a | One normal function and one decreased function allele; or One increased function and one decreased function allele; or Two decreased function alleles |
*1/*9, *1/*10, *9/*10 | Decreased compared to NM |
| Likely Poor metabolizers (PMs)a | One no function and one decreased function allele | *2/*9, *2/*10 | Markedly decreased |
| Poor metabolizers (PMs) | Two no function alleles | *2/*2, *3/*3, *8/*8 | Markedly decreased/absent |