The Genomics Revolution: Will This Mean a Resurgence of Customized Prescriptions?

To the Editor: The recent sequencing of the human genome is probably the greatest advance in medicine to date. In itself, however, this discovery will be of little significance until such a time as the specific function of each and every gene in the body has been fully mapped and ascertained. A great number of polymorphic genes are known (ie, genes whose form of presentation varies as between individuals) and, by extension, variations in the proteins that encode such genes. These proteins are usually responsible for drug metabolism or encoding cell receptors. This fact points to the possibility of adjusting drug dosage to the individual’s expected sensitivity based upon drug metabolism, and transporter and target polymorphisms. For instance, the CYP2C9 gene encodes the enzyme tasked with metabolizing many nonsteroidal anti-inflammatory drugs (NSAIDs) and warfarin, while the CYP2D6 gene participates in the metabolization of many antidepressants (1). Both genes belong to the cytochrome P450 superfamily. These two genes display well-described polymorphisms. In-