The 124 functional SNPs identified belong to 50 genes. These addiction susceptible genes are enriched in several functional categories such as focal adhesion (hyper-geometric test, p-Value = 0.02) that had been previously reported to be involved in drug addiction [21]. We compared these findings to findings from molecular biological studies extracted from the Knowledgebase for Addiction Related Genes (KARG) [21]. In KARG, 348 genes are linked to addiction susceptibility by at least two independent lines of molecular biologic evidence such as results from animal mutagenesis, microarray mRNA profiling and proteomics profiling. Only four genes were common between the two genetic association findings and the molecular biology findings (Official Symbol: FAAH, OPRM1, OPRK1, BDNF), consistent with previously observed modest overlaps between genetic and molecular biology findings in studies of other diseases [35].
