The novelty of this study requires a number of cautionary remarks. As noted in the introduction, GxD is conceptually similar to GxE, and likely shares many of the same pitfalls. One major hurdle is filtering candidate SNPs that show potential for GxD, and this is where the current study derives much of its strength. The longitudinal sample used in this report is quite small by GWAS standards, and could not by itself be used profitably to discover reliable GxD interactions against a background of 1 million SNPs. By leveraging results from the meta-analytic literature, which used tens of thousands of subjects, we were able to focus our GxD design only on highly promising SNPs that have high potential for replication.
