pharmacogenomics

Warfarin, a commonly used anti-clotting drug, sold under the brand name of Coumadin, has a been a poster child for the promise of pharmacogenomics and personalized medicine. The excitement has come from the idea that knowing a patient's genotype, in this case for the VKORC1 and CYP2C9 genes, would allow physicians to tailor the dose of the drug and get patients the correct dose more quickly. And it seems obvious that a test that would allow doctors to predict your ability to metabolize warfarin, would be a great thing, right? Figure 1. Human Cytochrome P450 Cyp2c9 bound to Warfarin…
Mark Henderson has a great piece in the Times exploring the impact of personal genomics on the practice of medicine. The basic theme should be familiar to anyone who has been following the emergence of the personal genomics industry: doctors are currently almost completely unprepared for the onslaught of genetic information they are about to experience. Here's the situation: At present, genetic training focuses on Mendelian diseases - rare mutations in single genes, which usually have severe effects. People who inherit the Huntington's mutation, for example, will invariably develop the…
Warfarin (a.k.a. Coumadin, Jantoven, Marevan, or Waran) is the most widely-prescribed blood-thinning agent on the market. It's also (in the words of Howard McLeod) a "terrible drug" - it has a very narrow therapeutic window, meaning that the minimal useful dose and the maximal safe dose are very close together. (The effects of over-dosing on warfarin - reduced blood clotting - are so severe that the drug is also used as a highly effective rat poison.) To further complicate things, the dosage of the drug that is both effective and safe differs widely between individuals, and is known to be…
In a comment on my previous post, Tera Eerkes is skeptical about the utility of routinely performing whole-genome sequencing on newborns: I found this comment absolutely fascinating, given the recent reports on translational analysis, that indicate an actual lack of clinical utility of KRAS testing and other drug-gene interactions. I believe these reports are indicative of a trend, not an exception. I think it is remarkable that anyone feels, even optimistically, that we're going to need a genome-wide scan for clinically useful indicators by 2019. I predict that there will be a…
The New York Times had a great article a couple of days ago on the need for personalized medicine to become more than a catchy phrase. As we're learning more about the interaction between genes and drug metabolism, we're also learning that large numbers of people are either taking the wrong drug or taking drugs that won't work. tags: personal genomics,pharmacogenomics Researchers have known for some time that genetic variants determine how well drugs work. Some versions of a gene cause a drug to be metabolized faster, some slower, and when combined, at an intermediate rate. In the…