Common diplotypesb | Expected population frequency, %c | PK/PD phenotype | Clinical phenotype | FDA guidelines | ||
---|---|---|---|---|---|---|
Caucasian ancestry | African ancestry | East Asian ancestry | ||||
CYP2C19*1/*1 | 38 | 35 | 35 | EM: normal enzymatic function and normal drug elimination | Likely to have normal response to standard dose of PPIs | – |
CYP2C19*1/*2, CYP2C19*1/*8, CYP2C19*2/*17, and other rare diplotypes (see Additional file 1: Table S7) | 26 | 31 | 48 | IM: reduced enzymatic function leading to reduced drug elimination and greater drug exposure | Both IM and PM likely to have improved PPI efficacy at standard dose of PPI as measured by intragastric pH, duration of inhibition, and cure rates for GERD and Helicobacter pylori | – |
CYP2C19*2/*2 and other rare diplotypes (see Additional file 1: Table S7) | 2 | 3.5 | 15 | PM: greatly reduced or abolished enzymatic function, leading to reduced drug elimination and greater drug exposure | – | |
CYP2C19*17/*17 | 5 | 4.5 | 0.04 | UM: enhanced enzymatic function leading to greater drug elimination and reduced drug exposure | Decreased PPI efficacy at standard doses | – |
CYP2C19*1/*17 | 29 | 26 | 2 | Unk: metabolizer status undetermined and therefore unknown; PD data shows platelet response is intermediate between IMs and EMs | Unknown effect on drug response | Â |