As more BMI-associated CpG sites are identified, the interaction between methylation and genetic profiles might become stronger, because it would be reasonable to expect that methylation at some of these CpGs might lie in the causal pathway, downstream of SNP effects. Further analysis to identify SNPs associated with both BMI and methylation levels at BMI-associated CpG sites would be needed to dissect the observed interaction and determine causality. Current work using a Mendelian randomization approach to identify a causal SNP (rs4925108) that is associated with methylation at a CpG site in SREBF suggests that both the SNP and the methylation levels at the CpG appear to be associated with BMI (M.M.M., unpublished data).