Pharmacogene: CYP2C19 
Type of pharmacogene: Pharmacokinetic

CYP2C19 codes for the drug-metabolizing enzyme CYP2C19. This enzyme is responsible for metabolizing approximately eight percent (8%) of medications. Variants of this pharmacogene may affect drug metabolism of substrate drugs.

Pharmacogene Variant of the Week (PVOW 12_7_2017): CYP2C19*17

Reference single nucleotide polymorphism number: rs12248560  

DNA base change: c.-806C>T   

Pharmacogene function as compared to normal function: Increased function

Pharmacogene product: CYP2C19 drug metabolizing enzyme

Pharmacogene product activity as compared to normal activity: Increased

General Conceptual Pharmacogene Variant Information

CYP2C19*17 Imparts:

Decreased drug exposure

- Lower maximum concentration

- Decreased area under the curve (AUC)

- Shorter half-life

Note: For a prodrug, less of the active drug will be formed.

Drug Exposure Plot

Note: "Increased" function/activity shown in relative terms.

Conceptual statement 1: Notwithstanding other variables, individuals with one (heterozygous) or two (homozygous) copies of this pharmacogene variant will likely have increased drug metabolism of an administered active drug, with decreased exposure and potential drug inefficacy.

Conceptual statement 2: Notwithstanding other variables, individuals with one (heterozygous) or two (homozygous) copies of this pharmacogene variant will likely have increased drug metabolism of an administered prodrug, with increased exposure to the active drug and potential increased risk of drug toxicity.

The reader is directed to https://www.pharmgkb.org/haplotype/PA166128332