Two new articles that just arrived in the new issue of the American Journal of Human Genetics caught my eye. Both articles deal with the serotonin system, and common genetic variants of the components of the system.The first article (McMahon et al) looks at patient responses to antidepression medicine (patients had major depressive disorder, medicine was citalopram). It was a big study; completing a genetic analysis of >1,900 patients and characterizing 768 different common genetic variants associated with 68 different genes. Of the 768 variants, they find that one common genetic variant associated with the serotonin 2A receptor seems to influence how well patients respond to the medicine. This is the sort of information that can be gathered now that the human genome project is finished and common genetic variants of different genes (a.k.a. SNPs) can be analyzed. Large scale analysis (1,000's of patients, hundreds of SNPs at a time) allow the entire genome to be scanned and associations to be made. The bottom line is that we will be able to (not too far in the future, when all this analysis is done) to look at the genetic makeup of a particular person and pick which medication is most likely to work.
The second paper looks at underlying genetic causes of obsessive-compulsive disorder (OCD). Almost all people with PWS at least have some symptoms of OCD, many have some pretty significant OCD behaviors. In this study, they were looking at another component of the serotonin system. They found that a particular genetic variation that in the transporter of serotonin was found more frequently in those with OCD. This study confirms and extends previous studies that implicated the serotonin system in OCD. American Jounal of Human Genetics - May 2006
Variation in the Gene Encoding the Serotonin 2A Receptor Is Associated with Outcome of Antidepressant Treatment
F J. McMahon, S Buervenich, D Charney, R Lipsky, AJ Rush, AF Wilson, AJ. M. Sorant, GJ Papanicolaou, G Laje, M Fava, MH Trivedi, SR Wisniewski, and H Manji (p804-814)
Serotonin Transporter Promoter Gain-of-Function Genotypes Are Linked to Obsessive-Compulsive Disorder
X-Z Hu, RH Lipsky, G Zhu, L A. Akhtar, J Taubman, BD Greenberg, K Xu, PD Arnold, MA. Richter, JL Kennedy, DL. Murphy, D Goldman (p815-826)