Using a replication approach, we identified a unique genome-wide significant risk region - SH3BP5-NR2C2 - for alcohol and nicotine co-dependence. This region was enriched with replicable risk SNPs in two genetically distinct populations. Additionally, the effect directions and significance strengths of all available SNPs across this whole region matched between two populations; that is, the distributions of -log(p) values for these markers were consistent between two populations, and the associations became more significant in meta-analysis. These findings suggested that SH3BP5-NR2C2 region might harbor causal loci for alcohol and nicotine co-dependence.
