TCF7 and Dravet syndrome: These data are consistent with a functional role for DNA methylation in modulating the expression of these genes in lymphocytes (and possibly in monocytes as well) and for the 3 genes from the PBL screen the directions of their changes in expression upon demethylation (increased for TMEM131 and NPDC1 and decreased for TCF7) match the predictions based on the differences of their average expression levels in DS versus normal PBL (Figure 4).