As is true of the current results, few previous studies of alcohol related phenotypes have identified replicable individual polymorphisms that meet genome-wide significance criteria. This is consistent with our understanding of the highly polygenic nature of alcohol problems: it is unlikely that individual common variants (MAF≥0.01) would have a large effect on the phenotype. Rather, hundreds if not thousands of variants influence risk. Risk variants are hypothesized to act in concert with one another in an additive or multiplicative fashion, and to be differentially influential in the context of environmental risk or protective factors.
