Online this week, Nature has published a genome-wide association study for response to treatment for chronic hepatitis C infection-the authors identify a polymorphism in an interleukin gene that is a strong predictor of how well an individual is able to clear the virus. Interestingly, the frequency of the polymorphism in different populations tracks the previously noted population difference in drug response, and the authors claim to explain half the difference in response rate between African- and European-Americans with this single polymorphism.

This paper is also interesting in that it represents one of the first (if not the first?) studies to coordinate a drug trial (in this cases, three different treatments for hepatitis C) with a genome-wide association study. This promises to lead to both important advances--as researchers are able to identify genetic subgroups of individuals who respond (or not) to a drug, even if it is ineffective in the population as a whole--as well as (my cynical side speaks) additional opportunities for misleading post hoc analyses by drug companies to try to salvage and market drugs that don't work. Hopefully, mostly the former--this could be an important step towards legitimizing genetic information in the eyes of MDs, and an ever-so-slight step towards personalized medicine.

Labels: Genetics