Pharmacogenetics Newsletter

Volume 1, Issue 10, 10/14/2009

Question

How do you interpret a single nucleotide polymorphism (SNPs) when reported in the medical literature? (ex. What does CYP2C19*3 mean and does it relate to its SNP, W212X (G636A)?)

Answer

In 2003 the Human Genome Project was completed and the mapping of the entire human DNA was made available to the public.(1)  As a result of this project, a number of biological influences on drug therapy can now be determined or identified.  One of those, is the identification of one of the most common genetic polymorphisms (variations) described in the literature and now being recognized in clinical practice, the single nucleotide polymorphisms (SNP; often pronounced, "Snips").  There are over 1 million SNPs in the human genome that occur at a frequency of 1% or greater in the general population.3  Unfortunately, it is now known how these genetic polymorphisms can directly influence a patient's response to drug therapy.