To discuss PGx, we must first define two terms:
- Cytochrome P450 (CYP450)
A polymorphism is a variation in a specific gene (allele) that affects at least 1% of the population. It is essentially a mutation that occurs relatively frequently in the population.
CYP450 refers to a family of enzymes found predominantly in the liver. CYP450 enzymes work on a variety of substrates (in this case, drugs), altering their chemical structures to facilitate excretion in the urine and feces. Many polymorphisms occur in the protein sequences of CYP450 enzymes.