CYP2C19 genotype-phenotype correlation: current insights and unanswered questions

The CYP2C19 enzyme is implicated in the metabolism of several clinically used drugs. Its phenotype is usually predicted by genotyping and indicates the expected enzymatic activity for each patient. However, with a few exceptions, CYP2C19 genotyping has not resulted in a reliable prediction of the metabolizer status, since most of the evidence currently available for this prediction comes from research into populations of predominantly European ancestry. Therefore, this review discusses the main factors that may alter the expected phenotype, as well as the urgent need to include ethnically diverse populations in further studies, so that, in the long term, it is possible to establish guidelines appropriate to these groups.